FLARM.....for good, or evil?? [Archive]

October 27th 10, 12:29 AM

On Oct 26, 3:11*pm, johngalloway > wrote:
> It is no great surprise that See and Avoid beats Flarm in busy thermal
> gaggles - that is what the manufacturers themselves advise - however I
> find that the general beeping really keeps my mind on lookout and I
> never silence it. *See page 12 on this PowerPoint presentation:
>
> http://www.flarm.com/files/basic_presentation_en.ppt
>
> As to Flarm induced complacency - this has been looked at in various
> reports and there is no evidence to support that notion - quite the
> reverse, Flarm seems to increase awareness of collision risk and
> encourage lookout. *Finding out how many gliders you wouldn't have
> been aware of without Flarms is a big eye opener.
>
> The question below about how 2 gliders can get very close without a
> Flarm alert sounding is easily and logically explained; Flarm is not a
> proximity alert, it is a potential collision course alert. *If two
> gliders are close to each other but not on a collision course there is
> no alert but if one then turns towards the other an alert will sound.
> How else would one want the device to be configured? *Two Flarmed
> gliders can cruise very close and parallel to each other (e.g. pair
> flying) with no alerts but as soon as they turn only a few degrees
> towards each other then the alarm sounds.
>
> John Galloway
>
> On 26 Oct, 18:47, " >
> wrote:
>
>
>
> > John,
>
> > I do not disagree with anything you say above. *I am glad you are
> > still alive. *I see the problem with big gaggles. *I think FLARM is a
> > useful tool in avoiding glider to glider collisions.
>
> > Well, I was thinking that maybe FLARM is creating false sense of
> > security? *Could contest pilots actually be tempted *to fly
> > dangerously, taking extra risks, assuming that if everybody has a
> > FLARM there is no problem??
>
> > How could two flarm equipped gliders possibly get within 10 feet of
> > each other? *I mean, at some earlier point in time they we
> > considerably further apart, so at what point does one or both pilots
> > take evasive action?
>
> > Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> > even closer?
>
> > Cookie- Hide quoted text -
>
> - Show quoted text -

John G.

So, are you suggesting that two gliders can come within 10 feet of
each other and neither receive a FLARM alarm?

Seems to me the simple fact that they were previously some distance
apart, then, later, only 10 feet apart, seems like converging flight
paths to me.

Cookie

[email protected]

October 27th 10, 12:38 AM

On Oct 26, 1:47*pm, "
> wrote:
> On Oct 26, 10:08*am, John Cochrane >
> wrote:
>
>
>
>
>
> > On Oct 26, 6:53*am, "
>
> > > wrote:
> > > From Sept 2010 "Soaring"...article on FLARM...
>
> > > ..."we were flying in big undiciplined gaggles"...
>
> > > ..."I received indications about one idiot who pulled in behind and
> > > then passed 10 feet over me."...
>
> > > ..."I received many beeps from gliders following 20 feet behind and
> > > just outside..."
>
> > > Holy close call Batman! *..Undisciplined??!! .. * Idiot??!! * ... 10
> > > feet over??!!.. * 20 feet??!!
>
> > > *Are you thinking what I'm thinking???
>
> > > Cookie
>
> > Well, I'm thinking I'm glad to be alive. I'm thinking that I like the
> > trend in US contest rules that take us away from mass gaggle flying,
> > and wish the worlds would take a stab in that direction as well. I'm
> > thinking flarm is a pretty darn good idea. What are you thinking?
>
> > John Cochrane
>
> John,
>
> I do not disagree with anything you say above. *I am glad you are
> still alive. *I see the problem with big gaggles. *I think FLARM is a
> useful tool in avoiding glider to glider collisions.
>
> Well, I was thinking that maybe FLARM is creating false sense of
> security? *Could contest pilots actually be tempted *to fly
> dangerously, taking extra risks, assuming that if everybody has a
> FLARM there is no problem??
>
> How could two flarm equipped gliders possibly get within 10 feet of
> each other? *I mean, at some earlier point in time they we
> considerably further apart, so at what point does one or both pilots
> take evasive action?
>
> Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> even closer?
>
> Cookie- Hide quoted text -
>
> - Show quoted text -

Hey Guys........

I think you are missing my point / question here............In my
original post, I did not intend to simply re-open the FALRM pro or con
arguement...Note I changed the heading.

My point / question is in regard to John C's article in soaring, in
which his accounts left me with a very uneasy feeling.

Not about the FLARM, but about what a perceive as possible misuse of
FLARM, or false confidence, or increased risk taking, knowing every
glider is FLARM equipped (that's the "evil" part in my heading).

I am referring to the parts in the article about "idiot" and
"undisciplined".....and what a perceive as some close, near
collisions........

Are the pilots "idiots" and "undisciplined" because of the FALRM? Or
are they "idiots" and "undisciplined" in spite of the FLARM?

Cookie

Ramy

October 27th 10, 01:29 AM

On Oct 26, 4:38*pm, "
> wrote:
> On Oct 26, 1:47*pm, "
>
>
>
>
>
> > wrote:
> > On Oct 26, 10:08*am, John Cochrane >
> > wrote:
>
> > > On Oct 26, 6:53*am, "
>
> > > > wrote:
> > > > From Sept 2010 "Soaring"...article on FLARM...
>
> > > > ..."we were flying in big undiciplined gaggles"...
>
> > > > ..."I received indications about one idiot who pulled in behind and
> > > > then passed 10 feet over me."...
>
> > > > ..."I received many beeps from gliders following 20 feet behind and
> > > > just outside..."
>
> > > > Holy close call Batman! *..Undisciplined??!! .. * Idiot??!! * .. 10
> > > > feet over??!!.. * 20 feet??!!
>
> > > > *Are you thinking what I'm thinking???
>
> > > > Cookie
>
> > > Well, I'm thinking I'm glad to be alive. I'm thinking that I like the
> > > trend in US contest rules that take us away from mass gaggle flying,
> > > and wish the worlds would take a stab in that direction as well. I'm
> > > thinking flarm is a pretty darn good idea. What are you thinking?
>
> > > John Cochrane
>
> > John,
>
> > I do not disagree with anything you say above. *I am glad you are
> > still alive. *I see the problem with big gaggles. *I think FLARM is a
> > useful tool in avoiding glider to glider collisions.
>
> > Well, I was thinking that maybe FLARM is creating false sense of
> > security? *Could contest pilots actually be tempted *to fly
> > dangerously, taking extra risks, assuming that if everybody has a
> > FLARM there is no problem??
>
> > How could two flarm equipped gliders possibly get within 10 feet of
> > each other? *I mean, at some earlier point in time they we
> > considerably further apart, so at what point does one or both pilots
> > take evasive action?
>
> > Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> > even closer?
>
> > Cookie- Hide quoted text -
>
> > - Show quoted text -
>
> Hey Guys........
>
> I think you are missing my point / question here............In my
> original post, I did not intend to simply re-open the FALRM pro or con
> arguement...Note I changed the heading.
>
> My point / question is in regard to John C's article in soaring, in
> which his accounts left me with a very uneasy feeling.
>
> Not about the FLARM, but about what a perceive as possible misuse of
> FLARM, or false confidence, or increased risk taking, knowing every
> glider is FLARM equipped *(that's the "evil" *part in my heading).
>
> I am referring to the parts in the article about "idiot" and
> "undisciplined".....and what a perceive as some close, near
> collisions........
>
> Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> are they "idiots" and "undisciplined" in spite of the FLARM?
>
> Cookie- Hide quoted text -
>
> - Show quoted text -

The answer to your question is the same as the answer to the following
question: Are you flying less carefully because you are wearing a
parachute? I don't think so.

Ramy

Ramy

October 27th 10, 01:37 AM

On Oct 26, 10:46*am, kd6veb > wrote:
> Hi Gang
> * Surely flying in a thermal with a gaggle of other gliders is
> suicidal period. And what use is a Flarm in those conditions? I have a
> Phoenix on order and am anticipating putting a PowerFlarm in it. Why?
> Because the PowerFlarm has a PCAS function in addition to the Flarm
> function and the PowerFlarm costs only a little more than a Zaon PCAS.
> I do think the mandatory use of Flarm is a good idea for comps
> especially if one can inexpensively rent a Flarm. But outside of comps
> with the flying I do having a transponder is by far the most important
> piece of safety equipment I have on board. A PCAS is also worth
> having. Having a Flarm? It is a useless device until the use of Flarm
> by the gliding community reaches critical mass (usage). That is
> unlikely to happen here in the US for several years at best. And then
> what about GA? What good is Flarm for GA? They are never going to use
> it in the US. The FAA has another system in store for GA and
> commercial aircraft.
> Dave

Dave, are you no longer flying to the Whites? Cause otherwise I am
sure you'll agree that in the area you are flying, other than near
Reno, the biggest risk of mid air collision is with another glider
running the White Mountains. On a good day, there can be over 20
gliders dolphine flying at 100 knots (200 knots closing speed) in a
1000 feet altitude band and within half a mile lateral, in both
directions.

Ramy

John Cochrane[_2_]

October 27th 10, 02:03 AM

>
> Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> are they "idiots" and "undisciplined" in spite of the FLARM?
>
> Cookie

My sense is that pilots at the worlds were flying the way they always
do. We were treated to daily briefings by Brian Spreckley with traces
and horror stories of near misses and collisions from all over Europe,
in contests with majority Flarm usage.

"Idiot" is perhaps a bit strong, and I may have been hasty in applying
it to a fellow pilot. On the other hand, he did pass 10-20 feet over
the top of my glider in a large gaggle. Perhaps he never saw me as
well. "Undisciplined" does stick. Really, when you know there are
20-30 gliders cruising together, one guy turning to the left and the
other of the pair turning to the right sets up 30 gliders turning in
both directions. Lots of people ignored all standard thermal
etiquette.

I think Flarm has a greater potential to seduce contest organizers
than pilots. Do you launch dozens of gliders into a low cloudbase; do
you set up multiple start areas or everyone start in one place; do you
set an assigned task which leads to more gaggling or an area task that
spreads people out more; do you worry about separating classes or
keep them on the same task; do you avoid out and return task legs, or
area tasks that set up flying up and down the same cloudstreet? Each
of these choices raises the chance of collisions, but are often
convenient for other reasons. Organizes and CDs may be tempted to
think, "well, they've all got Flarm, we can get away with it." I
hope we can fight this temptation.

John Cochrane

Larry Goddard

October 27th 10, 02:31 AM

"kd6veb" > wrote in message
:

> Hi Gang
> Surely flying in a thermal with a gaggle of other gliders is
> suicidal period.

Huh!? Are you serious? Or just trying to wind us up... ????

Larry

October 27th 10, 02:43 AM

On Oct 26, 9:03*pm, John Cochrane >
wrote:

> I think Flarm has a greater potential to seduce contest organizers
> than pilots. [...]

> Organizes and CDs may be tempted to
> think, "well, they've all got Flarm, we can get away with it." * I
> hope we can fight this temptation.
>
> John Cochrane

Well... maybe I'm just picking good contests... but I don't think
there's a chance in hell that *any* of the contest organizers I've
encountered in the last decade would take that attitude, consciously
or not.

-Evan Ludeman / T8

October 27th 10, 03:22 AM

On Oct 26, 10:46*am, kd6veb > wrote:
> what about GA? What good is Flarm for GA? They are never going to use
> it in the US. The FAA has another system in store for GA and
> commercial aircraft.

Seems to like cheap insurance for helicopters in metro areas as well
as airports with heavy training operations, as well as places such as
the Grand Canyon with heavy sightseeing operations. All of these
situations could easily get buy-in with a little bit of peer pressure
and local politics. Don't get the FAA involved, instead local pilot
groups and FBOs / commercial operators could make the case for
PowerFlarm as a useful tool for high density VFR operations. As
mentioned in other threads, ADS/B and ATC are just not designed for
these operations.

I recall that after the helicopter midair near Phoenix a few years
ago, there was a local news story of someone working on a $50K (fifty
thousand) solution to prevent these accidents.

Just my $0.02

-Tom

kd6veb

October 27th 10, 03:38 AM

On Oct 26, 5:37*pm, Ramy > wrote:
> On Oct 26, 10:46*am, kd6veb > wrote:
>
>
>
> > Hi Gang
> > * Surely flying in a thermal with a gaggle of other gliders is
> > suicidal period. And what use is a Flarm in those conditions? I have a
> > Phoenix on order and am anticipating putting a PowerFlarm in it. Why?
> > Because the PowerFlarm has a PCAS function in addition to the Flarm
> > function and the PowerFlarm costs only a little more than a Zaon PCAS.
> > I do think the mandatory use of Flarm is a good idea for comps
> > especially if one can inexpensively rent a Flarm. But outside of comps
> > with the flying I do having a transponder is by far the most important
> > piece of safety equipment I have on board. A PCAS is also worth
> > having. Having a Flarm? It is a useless device until the use of Flarm
> > by the gliding community reaches critical mass (usage). That is
> > unlikely to happen here in the US for several years at best. And then
Ramy wrote:
Dave, are you no longer flying to the Whites? Cause otherwise I am
sure you'll agree that in the area you are flying, other than near
Reno, the biggest risk of mid air collision is with another glider
running the White Mountains. On a good day, there can be over 20
gliders dolphine flying at 100 knots (200 knots closing speed) in a
1000 feet altitude band and within half a mile lateral, in both
directions.

Ramy
I fly the Whites with the transponder on like almost all responsible
glider pilots do. I also have PCAS on so if there is another pilot
near me with a transponder on I know that. Flarm is technically better
but why would we from the Reno area buy one having a transponder and
PCAS? I think you are missing the point of this discussion. Another
device that will only respond to other glider pilots having a Flarm?
This will not make sense to a large number of pilots who also want
protection from GA. I have said this many times but for us the
transponder is the most important safety device with PCAS a useful add
on. Flarm is a distant ( let me repeat that - A DISTANT THIRD) - on
the safety list of devices. I am not saying it is useless but until
about 50% of the glider pilots in the region you fly use one its
affect is marginal at best. That said I am purchasing one as I don't
see much downside for me but if I really had to tbe serious about
expenditures it would be a distant third on my list of safety devices
- transponder (90%), PCAS (8%) and guess where Flarm would be.
Dave

PS1 How are we going to persuade our FOBs at Minden to make the major
modification to Flarm when the installation of PowerFlarm in their
existing gliders may be difficult to say the least. The conversion to
transponders has been difficult enough for them and for Minden
transponders are clearly superior to Flarm. Hitting a commercial jet
with 200 passengers is not an option!

PS2 I wish risk management was taught in schools in the US.

> > what about GA? What good is Flarm for GA? They are never going to use
> > it in the US. The FAA has another system in store for GA and
> > commercial aircraft.
> > Dave
>
> Dave, are you no longer flying to the Whites? Cause otherwise I am
> sure you'll agree that in the area you are flying, other than near
> Reno, the biggest risk of mid air collision is with another glider
> running the White Mountains. On a good day, there can be over 20
> gliders dolphine flying at 100 knots (200 knots closing speed) in a
> 1000 feet altitude band and within half a mile lateral, in both
> directions.
>
> Ramy

[email protected]

October 27th 10, 03:53 AM

On Oct 26, 9:03*pm, John Cochrane >
wrote:
> > Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> > are they "idiots" and "undisciplined" in spite of the FLARM?
>
> > Cookie
>
> My sense is that pilots at the worlds were flying the way they always
> do. We were treated to daily briefings by Brian Spreckley with traces
> and horror stories of near misses and collisions from all over Europe,
> in contests with majority Flarm usage.
>
> "Idiot" is perhaps a bit strong, and I may have been hasty in applying
> it to a fellow pilot. On the other hand, he did pass 10-20 feet over
> the top of my glider in a large gaggle. Perhaps he never saw me as
> well. "Undisciplined" does stick. Really, when you know there are
> 20-30 gliders cruising together, one guy turning to the left and the
> other of the pair turning to the right sets up 30 gliders turning in
> both directions. Lots of people ignored all standard thermal
> etiquette.
>
> I think Flarm has a greater potential to seduce contest organizers
> than pilots. Do you launch dozens of gliders into a low cloudbase; do
> you set up multiple start areas or everyone start in one place; do you
> set an assigned task which leads to more gaggling or an area task that
> spreads people out *more; do you worry about separating classes or
> keep them on the same task; do you avoid out and return task legs, or
> area tasks that set up flying up and down the same cloudstreet? Each
> of these choices raises the chance of collisions, but are often
> convenient for other reasons. Organizes and CDs may be tempted to
> think, "well, they've all got Flarm, we can get away with it." * I
> hope we can fight this temptation.
>
> John Cochrane

John,

Thanks for the follow up..........I think we have two different
concerns brought up by your article.
1)Flarm,
2) bad, risky, dangerous flying

Again from your account, I figure FLARM is the way to
go............you wouldn't want to be in that environment without a
FLARM.........

But...........

I thought the bigger topic is safety, and collision
avoidence..................

The pilots in that contest seemed to have no concern for that.
"Idiot" is not too strong of a word.....No technology is going to work
if the pilots don't let it work!

Cookie

mattm[_2_]

October 27th 10, 03:57 AM

Mike Schumann

October 27th 10, 04:14 AM

On 10/26/2010 10:22 PM, 5Z wrote:
> On Oct 26, 10:46 am, > wrote:
>> what about GA? What good is Flarm for GA? They are never going to use
>> it in the US. The FAA has another system in store for GA and
>> commercial aircraft.
>
> Seems to like cheap insurance for helicopters in metro areas as well
> as airports with heavy training operations, as well as places such as
> the Grand Canyon with heavy sightseeing operations. All of these
> situations could easily get buy-in with a little bit of peer pressure
> and local politics. Don't get the FAA involved, instead local pilot
> groups and FBOs / commercial operators could make the case for
> PowerFlarm as a useful tool for high density VFR operations. As
> mentioned in other threads, ADS/B and ATC are just not designed for
> these operations.
>
> I recall that after the helicopter midair near Phoenix a few years
> ago, there was a local news story of someone working on a $50K (fifty
> thousand) solution to prevent these accidents.
>
> Just my $0.02
>
> -Tom
>
What would make you think that ADS-B was not designed for high density
VFR operations???? That's exactly what it was designed for, before the
FAA focused everyone's attention on using the technology to decrease
separations between IFR aircraft.

--
Mike Schumann

Darryl Ramm

October 27th 10, 05:29 AM

On Oct 26, 8:14*pm, Mike Schumann >
wrote:
> On 10/26/2010 10:22 PM, 5Z wrote:
>
> > On Oct 26, 10:46 am, > *wrote:
> >> what about GA? What good is Flarm for GA? They are never going to use
> >> it in the US. The FAA has another system in store for GA and
> >> commercial aircraft.
>
> > Seems to like cheap insurance for helicopters in metro areas as well
> > as airports with heavy training operations, as well as places such as
> > the Grand Canyon with heavy sightseeing operations. *All of these
> > situations could easily get buy-in with a little bit of peer pressure
> > and local politics. *Don't get the FAA involved, instead local pilot
> > groups and FBOs / commercial operators could make the case for
> > PowerFlarm as a useful tool for high density VFR operations. *As
> > mentioned in other threads, ADS/B and ATC are just not designed for
> > these operations.
>
> > I recall that after the helicopter midair near Phoenix a few years
> > ago, there was a local news story of someone working on a $50K (fifty
> > thousand) solution to prevent these accidents.
>
> > Just my $0.02
>
> > -Tom
>
> What would make you think that ADS-B was not designed for high density
> VFR operations???? *That's exactly what it was designed for, before the
> FAA focused everyone's attention on using the technology to decrease
> separations between IFR aircraft.
>
> --
> Mike Schumann

Do you have reference to any ADS-B work on close quarters flying, like
links you can give to research, design, testing etc. related to close
flying like say where you have helicopters orbiting a crime scene or
accident and which vendors make those systems? That scenario may be
like thermalling in gliders, if I operated news helicopters or similar
I'd be interested in checking a PowerFLARM (since they are such low
cost and don't involve any reglatory hassle) and seeing how it worked.
I'd also probalby want to look at ADS-B if I could would work out an
affordable/approved install to test with.

The big work in helicopters with ADS-B was the Gulf of Mexico trial
where the core there was really solving in-flight separation and
moving out of the "one in the slot" sequencing where they had no radar
offshore radar. By all accounts the GOMEX trial was pretty positive.

All the helicopter operators in any area would also need to get
together and agree on what ADS=B link-layer they will operate on
because where/how helicopters fly they are quite likely to be outside
GBT coverage and won't have any ADS-R service at times. But hopefully
that's a short meeting to get agreement on.

There is significant experience gained from GOMEX (Gulf of Mexico)
helicopter 1090ES operation. Again thanks to the FAA STC installation
are required for each helicopter type and ADS-B data-out equipment.
Some of the work was done for the GOMEX trial could probalby be
updated to meet a new STC. The issue there likely will be justifying
this STC development for some of the lighter helicopters that won't
have any work from GOMEX to piggy back on -- and Garmin's GTX-330ES
(probably the natural choice for light-medium helicopter avionics
given Gamin's push there recently) is not quite ready with DO-260B rev
yet so I don't see the FAA allowing a TSO until it is. I'm guessing
equipped price per light-medium helicopter for ADS-B data-out and -in
and display is likely to start in the $10k range (depends if the
helicopter has an existing TSO'ed WAAS GPS or an existing display
capability (I suspect a PDA is not going to cut it to a busy
helicopter crew)). Its unclear to me if the GPS used is specific in
the ADS-B data-out STC, if so that's may be another hurdle. There may
be question about display systems suitable for a no-hands helicopter
pilot.

The obstacle database in Flarm might also be interesting esp. for the
very light helicopters vs. existing relatively expensive GA TAWS
systems. But there is a question of getting the obstacle database in
Flarm format.

Darryl

Ramy

October 27th 10, 06:29 AM

On Oct 26, 7:38*pm, kd6veb > wrote:
> On Oct 26, 5:37*pm, Ramy > wrote:
>
>
>
> > On Oct 26, 10:46*am, kd6veb > wrote:
>
> > > Hi Gang
> > > * Surely flying in a thermal with a gaggle of other gliders is
> > > suicidal period. And what use is a Flarm in those conditions? I have a
> > > Phoenix on order and am anticipating putting a PowerFlarm in it. Why?
> > > Because the PowerFlarm has a PCAS function in addition to the Flarm
> > > function and the PowerFlarm costs only a little more than a Zaon PCAS..
> > > I do think the mandatory use of Flarm is a good idea for comps
> > > especially if one can inexpensively rent a Flarm. But outside of comps
> > > with the flying I do having a transponder is by far the most important
> > > piece of safety equipment I have on board. A PCAS is also worth
> > > having. Having a Flarm? It is a useless device until the use of Flarm
> > > by the gliding community reaches critical mass (usage). That is
> > > unlikely to happen here in the US for several years at best. And then
> *Ramy wrote:
>
> Dave, are you no longer flying to the Whites? Cause otherwise I am
> sure you'll agree that in the area you are flying, other than near
> Reno, the biggest risk of mid air collision is with another glider
> running the White Mountains. On a good day, there can be over 20
> gliders dolphine flying at 100 knots (200 knots closing speed) in a
> 1000 feet altitude band and within half a mile lateral, in both
> directions.
>
> Ramy
> * I fly the Whites with the transponder on like almost all responsible
> glider pilots do. I also have PCAS on so if there is another pilot
> near me with a transponder on I know that. Flarm is technically better
> but why would we from the Reno area buy one having a transponder and
> PCAS? I think you are missing the point of this discussion. Another
> device that will only respond to other glider pilots having a Flarm?
> This will not make sense to a large number of pilots who also want
> protection from GA. I have said this many times but for us the
> transponder is the most important safety device with PCAS a useful add
> on. Flarm is a distant ( let me repeat that - A DISTANT THIRD) - on
> the safety list of devices. I am not saying it is useless but until
> about 50% of the glider pilots in the region you fly use one its
> affect is marginal at best. That said I am purchasing one as I don't
> see much downside for me but if I really had to tbe serious about
> expenditures it would be a distant third on my list of safety devices
> - transponder (90%), PCAS (8%) and guess where Flarm would be.
> Dave
>
> PS1 How are we going to persuade our FOBs at Minden to make the major
> modification to Flarm when the installation of PowerFlarm in their
> existing gliders may be difficult to say the least. The conversion to
> transponders has been difficult enough for them and for Minden
> transponders are clearly superior to Flarm. Hitting a commercial jet
> with 200 passengers is not an option!
>
> PS2 I wish risk management was taught in schools in the US.
>
>
>
> > > what about GA? What good is Flarm for GA? They are never going to use
> > > it in the US. The FAA has another system in store for GA and
> > > commercial aircraft.
> > > Dave
>
> > Dave, are you no longer flying to the Whites? Cause otherwise I am
> > sure you'll agree that in the area you are flying, other than near
> > Reno, the biggest risk of mid air collision is with another glider
> > running the White Mountains. On a good day, there can be over 20
> > gliders dolphine flying at 100 knots (200 knots closing speed) in a
> > 1000 feet altitude band and within half a mile lateral, in both
> > directions.
>
> > Ramy- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

Gee Dave, looks like you are mixing between PCAS and TCAS!
Having flown with PCAS in the last 8 years (yes, even before MRX) I
can say that PCAS, until now, where the best and only colision
avoidance system available for gliders, and I would not fly without
one. But having said that, all the PCAS I flew with, including the
MRX, are unreliable, often do not alert you at all, or alert you way
too late (how many times it alerted me of other gliders AFTER they
passed me!), the audio alert often comes too late, the display alert
is hardly noticable unless you looking at it instead of outside, the
distance is very inacurate, the altitude difference is often
completely wrong, it will not alert you at all if there is no
interrogation, and even when everything works as designed, all you
know is that there is another aircraft nearby, but not WHERE. So the
best outcome of PCAS is that it encourages you to scan at the right
moment. That's it. And in case you suspect I have a faulty unit, mine
was at the factory nearly 5 times in the last 5 years, and got
completely replaced twice (great customer service though, they never
charged a dime).
Also Dave, I suggest reading a little more about PowerFlarm. Why do
you think a portbale device will be complicated to install?

Ramy

Darryl Ramm

October 27th 10, 06:37 AM

On Oct 26, 7:38*pm, kd6veb > wrote:
> On Oct 26, 5:37*pm, Ramy > wrote:
>
> > On Oct 26, 10:46*am, kd6veb > wrote:
>
> > > Hi Gang
> > > * Surely flying in a thermal with a gaggle of other gliders is
> > > suicidal period. And what use is a Flarm in those conditions? I have a
> > > Phoenix on order and am anticipating putting a PowerFlarm in it. Why?
> > > Because the PowerFlarm has a PCAS function in addition to the Flarm
> > > function and the PowerFlarm costs only a little more than a Zaon PCAS..
> > > I do think the mandatory use of Flarm is a good idea for comps
> > > especially if one can inexpensively rent a Flarm. But outside of comps
> > > with the flying I do having a transponder is by far the most important
> > > piece of safety equipment I have on board. A PCAS is also worth
> > > having. Having a Flarm? It is a useless device until the use of Flarm
> > > by the gliding community reaches critical mass (usage). That is
> > > unlikely to happen here in the US for several years at best. And then
> *Ramy wrote:
>
> Dave, are you no longer flying to the Whites? Cause otherwise I am
> sure you'll agree that in the area you are flying, other than near
> Reno, the biggest risk of mid air collision is with another glider
> running the White Mountains. On a good day, there can be over 20
> gliders dolphine flying at 100 knots (200 knots closing speed) in a
> 1000 feet altitude band and within half a mile lateral, in both
> directions.
>
> Ramy
> * I fly the Whites with the transponder on like almost all responsible
> glider pilots do. I also have PCAS on so if there is another pilot
> near me with a transponder on I know that. Flarm is technically better
> but why would we from the Reno area buy one having a transponder and
> PCAS? I think you are missing the point of this discussion. Another
> device that will only respond to other glider pilots having a Flarm?
> This will not make sense to a large number of pilots who also want
> protection from GA. I have said this many times but for us the
> transponder is the most important safety device with PCAS a useful add
> on. Flarm is a distant ( let me repeat that - A DISTANT THIRD) - on
> the safety list of devices. I am not saying it is useless but until
> about 50% of the glider pilots in the region you fly use one its
> affect is marginal at best. That said I am purchasing one as I don't
> see much downside for me but if I really had to tbe serious about
> expenditures it would be a distant third on my list of safety devices
> - transponder (90%), PCAS (8%) and guess where Flarm would be.
> Dave
>
> PS1 How are we going to persuade our FOBs at Minden to make the major
> modification to Flarm when the installation of PowerFlarm in their
> existing gliders may be difficult to say the least. The conversion to
> transponders has been difficult enough for them and for Minden
> transponders are clearly superior to Flarm. Hitting a commercial jet
> with 200 passengers is not an option!
>
> PS2 I wish risk management was taught in schools in the US.
>
> > > what about GA? What good is Flarm for GA? They are never going to use
> > > it in the US. The FAA has another system in store for GA and
> > > commercial aircraft.
> > > Dave
>
> > Dave, are you no longer flying to the Whites? Cause otherwise I am
> > sure you'll agree that in the area you are flying, other than near
> > Reno, the biggest risk of mid air collision is with another glider
> > running the White Mountains. On a good day, there can be over 20
> > gliders dolphine flying at 100 knots (200 knots closing speed) in a
> > 1000 feet altitude band and within half a mile lateral, in both
> > directions.
>
> > Ramy
>
>

It has been a few years since I've been on the Whites, but I've done
that enough times with a transponder and PCAS and with enough other
gliders all with different levels of transponder and PCAS equipage
that I can say its a helpful warning at times but also scary how
poorly it works as well when running at high speed close to the rocks
with lots of other gliders around. It's out little part of the
European Alps glider traffic problem relocated to sunny California.
You can be getting PCAS alerts from gliders behind you and miss the
one coming head on at you until too late. The lack of directional
clues have you sweating if that new alert at exactly your altitude is
ahead or behind you - since as Ramy points out everybody often ends up
on the same race track . There are also locations where you round an
obstruction and then are surprised by a glider coming the other way
but you never say its transponder because you did not have line of
sight. Flarm will have a similar issue with only line of sight
coverage but the huge difference is that as soon as you get line of
sight you get immediate (~< 1 sec) information including direction to
any threat and the threat assessment is much more sophisticated. It
should be no surprise that PCAS has problems in this type scenario, it
is just not really intended for this - something Flarm is used for
widely in Europe.

Dave I assume you are trolling here a bit for fun since you've tried
to stir up similar discussions on other forums and then made clear you
already have decided to buy a PowerFLARM. You guys should be working
on a bulk-buy for PowerFLARM out of Minden and see how much real
interest there is there. A significant number of the SF Bay Area
pilots who do serous XC out of the Reno/Miden/Truckee area have
committed to purchase PowerFLARM arleady and its early days yet -- so
far I count around 15 committed purchases from SF Bay Area/Central
Valley pilots who fly serious XC out of the Reno/Minden/Truckee area
during summer - and almost every one to a man has a transponder
already (I am aware of one who does not -- and he knows who he is and
he plans to fix that as well :-)). I don't have a feel for local
Minden/Truckee pilot purchase plans -- but I hope to see enough of you
guys at this Saturday's PASCO saftey seminar that we can talk about it
live.

Regards

Darryl

[email protected]

October 27th 10, 12:15 PM

On Oct 26, 8:29*pm, Ramy > wrote:
> On Oct 26, 4:38*pm, "
>
>
>
>
>
> > wrote:
> > On Oct 26, 1:47*pm, "
>
> > > wrote:
> > > On Oct 26, 10:08*am, John Cochrane >
> > > wrote:
>
> > > > On Oct 26, 6:53*am, "
>
> > > > > wrote:
> > > > > From Sept 2010 "Soaring"...article on FLARM...
>
> > > > > ..."we were flying in big undiciplined gaggles"...
>
> > > > > ..."I received indications about one idiot who pulled in behind and
> > > > > then passed 10 feet over me."...
>
> > > > > ..."I received many beeps from gliders following 20 feet behind and
> > > > > just outside..."
>
> > > > > Holy close call Batman! *..Undisciplined??!! .. * Idiot??!! * .. 10
> > > > > feet over??!!.. * 20 feet??!!
>
> > > > > *Are you thinking what I'm thinking???
>
> > > > > Cookie
>
> > > > Well, I'm thinking I'm glad to be alive. I'm thinking that I like the
> > > > trend in US contest rules that take us away from mass gaggle flying,
> > > > and wish the worlds would take a stab in that direction as well. I'm
> > > > thinking flarm is a pretty darn good idea. What are you thinking?
>
> > > > John Cochrane
>
> > > John,
>
> > > I do not disagree with anything you say above. *I am glad you are
> > > still alive. *I see the problem with big gaggles. *I think FLARM is a
> > > useful tool in avoiding glider to glider collisions.
>
> > > Well, I was thinking that maybe FLARM is creating false sense of
> > > security? *Could contest pilots actually be tempted *to fly
> > > dangerously, taking extra risks, assuming that if everybody has a
> > > FLARM there is no problem??
>
> > > How could two flarm equipped gliders possibly get within 10 feet of
> > > each other? *I mean, at some earlier point in time they we
> > > considerably further apart, so at what point does one or both pilots
> > > take evasive action?
>
> > > Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> > > even closer?
>
> > > Cookie- Hide quoted text -
>
> > > - Show quoted text -
>
> > Hey Guys........
>
> > I think you are missing my point / question here............In my
> > original post, I did not intend to simply re-open the FALRM pro or con
> > arguement...Note I changed the heading.
>
> > My point / question is in regard to John C's article in soaring, in
> > which his accounts left me with a very uneasy feeling.
>
> > Not about the FLARM, but about what a perceive as possible misuse of
> > FLARM, or false confidence, or increased risk taking, knowing every
> > glider is FLARM equipped *(that's the "evil" *part in my heading).
>
> > I am referring to the parts in the article about "idiot" and
> > "undisciplined".....and what a perceive as some close, near
> > collisions........
>
> > Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> > are they "idiots" and "undisciplined" in spite of the FLARM?
>
> > Cookie- Hide quoted text -
>
> > - Show quoted text -
>
> The answer to your question is the same as the answer to the following
> question: Are you flying less carefully because you are wearing a
> parachute? I don't think so.
>
> Ramy- Hide quoted text -
>
> - Show quoted text -

Ramy,

I disagree ..........With a parachute I do take more risk......and you
probably do to.

Here are three examples of more risky flying WITH a parachute that I
do / have done:

1) Flight testing homebuilt aircraft
2) Aerobatic flying
3) Glider competition

Regualtion and / or common sense dictates a parachute for the above
scenarios.

Cookie

cernauta

October 27th 10, 12:28 PM

On Tue, 26 Oct 2010 16:29:23 -0700 (PDT), "
> wrote:

>
>So, are you suggesting that two gliders can come within 10 feet of
>each other and neither receive a FLARM alarm?
>
>Seems to me the simple fact that they were previously some distance
>apart, then, later, only 10 feet apart, seems like converging flight
>paths to me.

Yes, you can get very close to a glider without Flarm to warn you (in
alarm mode). It's a matter of speeds and heading. You can fly long
distances, on a ridge for examples, leeching or side by side; you only
get occasional warnings when the paths change.

in "awareness mode", of course a led will indicate where the closer
glider is, but still alarms will only be triggered when a deviation
makes the collision a real possibility.

aldo cernezzi

Mike Schumann

October 27th 10, 02:06 PM

On 10/27/2010 12:29 AM, Darryl Ramm wrote:
> On Oct 26, 8:14 pm, Mike >
> wrote:
>> On 10/26/2010 10:22 PM, 5Z wrote:
>>
>>> On Oct 26, 10:46 am, > wrote:
>>>> what about GA? What good is Flarm for GA? They are never going to use
>>>> it in the US. The FAA has another system in store for GA and
>>>> commercial aircraft.
>>
>>> Seems to like cheap insurance for helicopters in metro areas as well
>>> as airports with heavy training operations, as well as places such as
>>> the Grand Canyon with heavy sightseeing operations. All of these
>>> situations could easily get buy-in with a little bit of peer pressure
>>> and local politics. Don't get the FAA involved, instead local pilot
>>> groups and FBOs / commercial operators could make the case for
>>> PowerFlarm as a useful tool for high density VFR operations. As
>>> mentioned in other threads, ADS/B and ATC are just not designed for
>>> these operations.
>>
>>> I recall that after the helicopter midair near Phoenix a few years
>>> ago, there was a local news story of someone working on a $50K (fifty
>>> thousand) solution to prevent these accidents.
>>
>>> Just my $0.02
>>
>>> -Tom
>>
>> What would make you think that ADS-B was not designed for high density
>> VFR operations???? That's exactly what it was designed for, before the
>> FAA focused everyone's attention on using the technology to decrease
>> separations between IFR aircraft.
>>
>> --
>> Mike Schumann
>
> Do you have reference to any ADS-B work on close quarters flying, like
> links you can give to research, design, testing etc. related to close
> flying like say where you have helicopters orbiting a crime scene or
> accident and which vendors make those systems? That scenario may be
> like thermalling in gliders, if I operated news helicopters or similar
> I'd be interested in checking a PowerFLARM (since they are such low
> cost and don't involve any reglatory hassle) and seeing how it worked.
> I'd also probalby want to look at ADS-B if I could would work out an
> affordable/approved install to test with.
>
> The big work in helicopters with ADS-B was the Gulf of Mexico trial
> where the core there was really solving in-flight separation and
> moving out of the "one in the slot" sequencing where they had no radar
> offshore radar. By all accounts the GOMEX trial was pretty positive.
>
> All the helicopter operators in any area would also need to get
> together and agree on what ADS=B link-layer they will operate on
> because where/how helicopters fly they are quite likely to be outside
> GBT coverage and won't have any ADS-R service at times. But hopefully
> that's a short meeting to get agreement on.
>
> There is significant experience gained from GOMEX (Gulf of Mexico)
> helicopter 1090ES operation. Again thanks to the FAA STC installation
> are required for each helicopter type and ADS-B data-out equipment.
> Some of the work was done for the GOMEX trial could probalby be
> updated to meet a new STC. The issue there likely will be justifying
> this STC development for some of the lighter helicopters that won't
> have any work from GOMEX to piggy back on -- and Garmin's GTX-330ES
> (probably the natural choice for light-medium helicopter avionics
> given Gamin's push there recently) is not quite ready with DO-260B rev
> yet so I don't see the FAA allowing a TSO until it is. I'm guessing
> equipped price per light-medium helicopter for ADS-B data-out and -in
> and display is likely to start in the $10k range (depends if the
> helicopter has an existing TSO'ed WAAS GPS or an existing display
> capability (I suspect a PDA is not going to cut it to a busy
> helicopter crew)). Its unclear to me if the GPS used is specific in
> the ADS-B data-out STC, if so that's may be another hurdle. There may
> be question about display systems suitable for a no-hands helicopter
> pilot.
>
> The obstacle database in Flarm might also be interesting esp. for the
> very light helicopters vs. existing relatively expensive GA TAWS
> systems. But there is a question of getting the obstacle database in
> Flarm format.
>
> Darryl
>

There's a difference between flying in high density VFR environments and
close quarters flying. Flying in the pattern at a very busy GA airport
is not nearly as challenging as flying in a gaggle with numerous other
gliders.

Neither ADS-B nor FLARM can provide foolproof collision protection
between gliders sharing a thermal. Urs, Rob Strain and I had a
discussion about this at the SSA convention in Albuquerque a number of
years ago. This is a fundamental problem of GPS accuracy limits,
coupled with how far a glider can move in an unexpected direction
between the 1 sec position updates.

That's not to say that FLARM or ADS-B can't be helpful in notifying you
of new aircraft (gliders or GA) approaching a gaggle, so you can keep an
eye out, or in letting you see how many gliders are in a gaggle and
their relative orientation when you are approaching.

--
Mike Schumann

cernauta

October 27th 10, 02:34 PM

On Wed, 27 Oct 2010 09:06:31 -0400, Mike Schumann
> wrote:

>Neither ADS-B nor FLARM can provide foolproof collision protection
>between gliders sharing a thermal.
....
>That's not to say that FLARM or ADS-B can't be helpful in notifying you
>of new aircraft (gliders or GA) approaching a gaggle, so you can keep an
>eye out, or in letting you see how many gliders are in a gaggle and
>their relative orientation when you are approaching.

I agree. In facts, I think we don't NEED any "foolproof collision
protection". I also believe that we don't need Flarm to be infallible.
If it will warn me from relatively distant gliders I have already
seen, and which don't seem to be a threat, I'll say "thanks pal, I
already knew about him".

The accidents that have happened are the proof that, however, we NEED
a device to turn our attention on, when it might momentarily,
unvoluntarily and unawarely be off.

I recall an old, dramatic report which appeared in Soaring magazine.
It was written by the survivor of a glider-glider collision. They had
been flying together since taking off, so they both were well aware of
the traffic. Not a lot of VFR traffic, not a huge gaggle, not a
densely participated competition. Just two gliders.
Nevertheless, while searching for lift, they collided.

Would Flarm have been available at the time, and installed in both
gliders, it most probably would have turned into a non-event, less
than an incident.
We just wouldn't think about it today, and the gliding community would
have one more member and less sorrow. I see no reason to wait longer
before takeing advantage of this technology. We've been using it for
many years now, in Europe.

Aldo Cernezzi

[email protected]

October 27th 10, 03:20 PM

On Oct 27, 7:28*am, cernauta > wrote:
> On Tue, 26 Oct 2010 16:29:23 -0700 (PDT), "
>
> > wrote:
>
> >So, are you suggesting that two gliders can come within 10 feet of
> >each other and neither receive a FLARM alarm?
>
> >Seems to me the simple fact that they were previously some distance
> >apart, then, later, only 10 feet apart, seems like converging flight
> >paths to me.
>
> Yes, you can get very close to a glider without Flarm to warn you (in
> alarm mode). It's a matter of speeds and heading. You can fly long
> distances, on a ridge for examples, leeching or side by side; you only
> get occasional warnings when the paths change.
>
> in "awareness mode", of course a led will indicate where the closer
> glider is, but still alarms will only be triggered when a deviation
> makes the collision a real possibility.
>
> aldo cernezzi

Since the GPS accuracy is probably much poorer than 10 feet, when a
glider comes within 10 feet, I figure the FLARM should consider that a
collision, no?

Cookie

John Smith

October 27th 10, 03:23 PM

wrote:
> Since the GPS accuracy is probably much poorer than 10 feet, when a
> glider comes within 10 feet, I figure the FLARM should consider that a
> collision, no?

I don't know about yours, but my glider's span is more than 10 feet...

Kevin Christner

October 27th 10, 03:45 PM

On Oct 27, 4:15*am, "
> wrote:
> On Oct 26, 8:29*pm, Ramy > wrote:
>
>
>
>
>
> > On Oct 26, 4:38*pm, "
>
> > > wrote:
> > > On Oct 26, 1:47*pm, "
>
> > > > wrote:
> > > > On Oct 26, 10:08*am, John Cochrane >
> > > > wrote:
>
> > > > > On Oct 26, 6:53*am, "
>
> > > > > > wrote:
> > > > > > From Sept 2010 "Soaring"...article on FLARM...
>
> > > > > > ..."we were flying in big undiciplined gaggles"...
>
> > > > > > ..."I received indications about one idiot who pulled in behind and
> > > > > > then passed 10 feet over me."...
>
> > > > > > ..."I received many beeps from gliders following 20 feet behind and
> > > > > > just outside..."
>
> > > > > > Holy close call Batman! *..Undisciplined??!! .. * Idiot??!! * .. 10
> > > > > > feet over??!!.. * 20 feet??!!
>
> > > > > > *Are you thinking what I'm thinking???
>
> > > > > > Cookie
>
> > > > > Well, I'm thinking I'm glad to be alive. I'm thinking that I like the
> > > > > trend in US contest rules that take us away from mass gaggle flying,
> > > > > and wish the worlds would take a stab in that direction as well. I'm
> > > > > thinking flarm is a pretty darn good idea. What are you thinking?
>
> > > > > John Cochrane
>
> > > > John,
>
> > > > I do not disagree with anything you say above. *I am glad you are
> > > > still alive. *I see the problem with big gaggles. *I think FLARM is a
> > > > useful tool in avoiding glider to glider collisions.
>
> > > > Well, I was thinking that maybe FLARM is creating false sense of
> > > > security? *Could contest pilots actually be tempted *to fly
> > > > dangerously, taking extra risks, assuming that if everybody has a
> > > > FLARM there is no problem??
>
> > > > How could two flarm equipped gliders possibly get within 10 feet of
> > > > each other? *I mean, at some earlier point in time they we
> > > > considerably further apart, so at what point does one or both pilots
> > > > take evasive action?
>
> > > > Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> > > > even closer?
>
> > > > Cookie- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Hey Guys........
>
> > > I think you are missing my point / question here............In my
> > > original post, I did not intend to simply re-open the FALRM pro or con
> > > arguement...Note I changed the heading.
>
> > > My point / question is in regard to John C's article in soaring, in
> > > which his accounts left me with a very uneasy feeling.
>
> > > Not about the FLARM, but about what a perceive as possible misuse of
> > > FLARM, or false confidence, or increased risk taking, knowing every
> > > glider is FLARM equipped *(that's the "evil" *part in my heading)..
>
> > > I am referring to the parts in the article about "idiot" and
> > > "undisciplined".....and what a perceive as some close, near
> > > collisions........
>
> > > Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> > > are they "idiots" and "undisciplined" in spite of the FLARM?
>
> > > Cookie- Hide quoted text -
>
> > > - Show quoted text -
>
> > The answer to your question is the same as the answer to the following
> > question: Are you flying less carefully because you are wearing a
> > parachute? I don't think so.
>
> > Ramy- Hide quoted text -
>
> > - Show quoted text -
>
> Ramy,
>
> I disagree ..........With a parachute I do take more risk......and you
> probably do to.
>
> Here are three examples of more risky flying WITH a parachute that I
> do / have done:
>
> 1) Flight testing homebuilt aircraft
> 2) Aerobatic flying
> 3) Glider competition
>
> Regualtion and / or common sense dictates a parachute for the above
> scenarios.
>
> Cookie

You are confusing cause and effect. Your CHOICE to take more risk
CAUSES you to wear a parachute. Your CHOICE to fly in competition
will CAUSE (force) you to use a FLARM. You made choices independent
of equipment. The equipment didnt cause you to take more risk.

2C

John Smith

October 27th 10, 04:04 PM

wrote:
> Here are three examples of more risky flying WITH a parachute that I
> do / have done:

> 2) Aerobatic flying
> 3) Glider competition

Off topic, but it makes me always wonder. To me, simple plain cross
country flying is by far the most dangerous way to operate a glider. At
least as risky as competition and certainly far more risky than
aerobatics. But as I said, off topic.

Ramy

October 27th 10, 04:53 PM

On Oct 27, 4:15*am, "
> wrote:
> On Oct 26, 8:29*pm, Ramy > wrote:
>
>
>
>
>
> > On Oct 26, 4:38*pm, "
>
> > > wrote:
> > > On Oct 26, 1:47*pm, "
>
> > > > wrote:
> > > > On Oct 26, 10:08*am, John Cochrane >
> > > > wrote:
>
> > > > > On Oct 26, 6:53*am, "
>
> > > > > > wrote:
> > > > > > From Sept 2010 "Soaring"...article on FLARM...
>
> > > > > > ..."we were flying in big undiciplined gaggles"...
>
> > > > > > ..."I received indications about one idiot who pulled in behind and
> > > > > > then passed 10 feet over me."...
>
> > > > > > ..."I received many beeps from gliders following 20 feet behind and
> > > > > > just outside..."
>
> > > > > > Holy close call Batman! *..Undisciplined??!! .. * Idiot??!! * .. 10
> > > > > > feet over??!!.. * 20 feet??!!
>
> > > > > > *Are you thinking what I'm thinking???
>
> > > > > > Cookie
>
> > > > > Well, I'm thinking I'm glad to be alive. I'm thinking that I like the
> > > > > trend in US contest rules that take us away from mass gaggle flying,
> > > > > and wish the worlds would take a stab in that direction as well. I'm
> > > > > thinking flarm is a pretty darn good idea. What are you thinking?
>
> > > > > John Cochrane
>
> > > > John,
>
> > > > I do not disagree with anything you say above. *I am glad you are
> > > > still alive. *I see the problem with big gaggles. *I think FLARM is a
> > > > useful tool in avoiding glider to glider collisions.
>
> > > > Well, I was thinking that maybe FLARM is creating false sense of
> > > > security? *Could contest pilots actually be tempted *to fly
> > > > dangerously, taking extra risks, assuming that if everybody has a
> > > > FLARM there is no problem??
>
> > > > How could two flarm equipped gliders possibly get within 10 feet of
> > > > each other? *I mean, at some earlier point in time they we
> > > > considerably further apart, so at what point does one or both pilots
> > > > take evasive action?
>
> > > > Or does FLARM somehow allow safe flight within 20 feet or 10 feet or
> > > > even closer?
>
> > > > Cookie- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Hey Guys........
>
> > > I think you are missing my point / question here............In my
> > > original post, I did not intend to simply re-open the FALRM pro or con
> > > arguement...Note I changed the heading.
>
> > > My point / question is in regard to John C's article in soaring, in
> > > which his accounts left me with a very uneasy feeling.
>
> > > Not about the FLARM, but about what a perceive as possible misuse of
> > > FLARM, or false confidence, or increased risk taking, knowing every
> > > glider is FLARM equipped *(that's the "evil" *part in my heading)..
>
> > > I am referring to the parts in the article about "idiot" and
> > > "undisciplined".....and what a perceive as some close, near
> > > collisions........
>
> > > Are the pilots "idiots" and "undisciplined" because of the FALRM? *Or
> > > are they "idiots" and "undisciplined" in spite of the FLARM?
>
> > > Cookie- Hide quoted text -
>
> > > - Show quoted text -
>
> > The answer to your question is the same as the answer to the following
> > question: Are you flying less carefully because you are wearing a
> > parachute? I don't think so.
>
> > Ramy- Hide quoted text -
>
> > - Show quoted text -
>
> Ramy,
>
> I disagree ..........With a parachute I do take more risk......and you
> probably do to.
>
> Here are three examples of more risky flying WITH a parachute that I
> do / have done:
>
> 1) Flight testing homebuilt aircraft
> 2) Aerobatic flying
> 3) Glider competition
>
> Regualtion and / or common sense dictates a parachute for the above
> scenarios.
>
> Cookie

So are you suggesting that parachutes are also evil?
Cookie I think you confuses activities with behavior. Of course more
pilots may also fly contests with Flarm.

Martin Gregorie[_5_]

October 27th 10, 04:54 PM

On Wed, 27 Oct 2010 17:04:13 +0200, John Smith wrote:

> wrote:
>> Here are three examples of more risky flying WITH a parachute that I do
>> / have done:
>
>> 2) Aerobatic flying
> > 3) Glider competition
>
> Off topic, but it makes me always wonder. To me, simple plain cross
> country flying is by far the most dangerous way to operate a glider. At
> least as risky as competition and certainly far more risky than
> aerobatics. But as I said, off topic.
>
That surely depends on the circumstances:

- if you're flying in a flat part of the country after the crops
have been harvested that XC is only slightly more risky than
local soaring in normal Sunday afternoon conditions.

- OTOH during the UK's foot & Mouth outbreak in 2001 when only local
soaring was permitted the air round our field no only got distinctly
busy, but on the frequent weak days we had massed landings as well.
During this period local soaring involved considerably more risk than
normal XC flying does in our area.

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Ramy

October 27th 10, 05:07 PM

On Oct 27, 8:04*am, John Smith > wrote:
> wrote:
> > Here are three examples of more risky flying WITH a parachute that I
> > do / have done:
> > 2) Aerobatic flying
>
> *> 3) Glider competition
>
> Off topic, but it makes me always wonder. To me, simple plain cross
> country flying is by far the most dangerous way to operate a glider. At
> least as risky as competition and certainly far more risky than
> aerobatics. But as I said, off topic.

Competition IS cross country flying plus additional constrains
(gaggles, tasks, more traffic, pressure to complete the task etc etc)
how could this make it safer than plain cross country? Are you
suggesting that contest director knows more about the weather and
risks than the pilots? But I agree, this is off topic.

Ramy

sisu1a

October 27th 10, 05:24 PM

> To me, simple plain cross
> country flying is by far the most dangerous way to operate a glider. At
> least as risky as competition and certainly far more risky than
> aerobatics.

Huh? Your logic escapes me. Comp flying IS X/C flying, but with the
added element of being adrenalin saturated, pushing it faster, and
now sharing the air with 20-150 other gliders doing the same thing on
the same course, with some course legs potentially overlapping and
opposing other legs. How does regular X/C flying even come close to
this? (perhaps this should be it's own thread?)

As a pilot with acro tendencies, I also disagree with the risk levels
being on par with X/C. Acro flying removes most of the variables that
make X/C flying more likely to bite you or your ship (scratching low
for lift, stretching glides, running ridges, landing out, etc) than
say flying within the vicinity of your local airport. In USA, acro is
done above 1500ft agl, and with a chute, outside of controlled
airspace and not above dense populations, although it does add a risk
of it's own; the increased chance of structural damage. I firmly
believe acro flying teaches/promotes life saving skills and reflexes
(upset attitudes ans such) that carry over into all other flying the
same way wringing out your car on a skidpad after some advanced driver
training will leave you better equipped to deal with unexpected road
emergencies.

tl:dr: comp flying is X/C on steroids and hence more risky but acro
involves less risks than regular X/C and adds useful skills...

-Paul

ps. those promoting the seatbelt-logic-fallacy should be ashamed...

sisu1a

October 27th 10, 05:29 PM

> > To me, simple plain cross
> > country flying is by far the most dangerous way to operate a glider. At
> > least as risky as competition and certainly far more risky than
> > aerobatics.
>
> Huh? Your logic escapes me. Comp flying IS X/C flying, but with the
> added element of being adrenalin saturated, *pushing it faster, and
> now sharing the air with 20-150 other gliders doing the same thing on
> the same course, with some course legs potentially overlapping and
> opposing other legs. How does regular X/C flying even come close to
> this? (perhaps this should be it's own thread?)
>
> As a pilot with acro tendencies, I also disagree with the risk levels
> being on par with X/C. Acro flying removes most of the variables that
> make X/C flying more likely to bite you or your ship (scratching low
> for lift, stretching glides, running ridges, landing out, etc) than
> say flying within the vicinity of your local airport. In USA, acro is
> done above 1500ft agl, and with a chute, outside of controlled
> airspace and not above dense populations, although it does add a risk
> of it's own; the increased chance of structural damage. I firmly
> believe acro flying teaches/promotes life saving skills and reflexes
> (upset attitudes ans such) that carry over into all other flying the
> same way wringing out your car on a skidpad after some advanced driver
> training will leave you better equipped to deal with unexpected road
> emergencies.
>
> tl:dr: comp flying is X/C on steroids and hence more risky but acro
> involves less risks than regular X/C and adds useful skills...
>
> -Paul
>
> ps. those promoting the seatbelt-logic-fallacy should be ashamed...

Oops... sorry John, read closer and now see we do have the same basic
view on acro flying vs X/C, my bad. A stand by my analysis though...

Bruce Hoult

October 27th 10, 05:39 PM

On Oct 28, 4:04*am, John Smith > wrote:
> wrote:
> > Here are three examples of more risky flying WITH a parachute that I
> > do / have done:
> > 2) Aerobatic flying
> *> 3) Glider competition
>
> Off topic, but it makes me always wonder. To me, simple plain cross
> country flying is by far the most dangerous way to operate a glider. At
> least as risky as competition and certainly far more risky than
> aerobatics. But as I said, off topic.

What do you consider dangerous in cross country flying?

I presume it's not mid air collisions, as that is much of what makes
competition more dangerous.

I presume it's not risk of the glider falling apart in mid air, as
most cross country is done at quite modest speeds and low G loadings.

So then ... landouts?

If that is what concerns you then I'm puzzled. At the point that
you're contemplating a landout, a parachute is of no use whatsoever.

John Smith

October 27th 10, 06:39 PM

Bruce Hoult wrote:
> What do you consider dangerous in cross country flying?

I've lost three friends by midairs during leisure cross country flying
but none during competition flying (all in Pre-FLARM-age). That's just
my purely personal, anectotcal and irrelevant statistics.

Where I fly, there are "glider highways" which can be pretty crowded on
thermally active weekends. With the difference that competition pilots
tend to be 100% awake, which cannot always be said of leisure pilots on
an 8 hour leisure flight. Interesting is that one of the midairs
mentioned above didn't happen on such a highway, but out in the nowhere
after the two gliders both had happily cruised along on a straight track
for several minutes (as the logger file showed), until they happened to
be in the same place at the same time. Again just my purely personal,
anectotical and irrelevant experience.

Back to the topic: I'm convinced that all three would still be alive had
FLARM already existed.

mattm[_2_]

October 27th 10, 08:18 PM

On Oct 27, 1:39*pm, John Smith > wrote:
> Bruce Hoult wrote:
> > What do you consider dangerous in cross country flying?
>
> I've lost three friends by midairs during leisure cross country flying
> but none during competition flying (all in Pre-FLARM-age). That's just
> my purely personal, anectotcal and irrelevant statistics.
>
> Where I fly, there are "glider highways" which can be pretty crowded on
> thermally active weekends. With the difference that competition pilots
> tend to be 100% awake, which cannot always be said of leisure pilots on
> an 8 hour leisure flight. Interesting is that one of the midairs
> mentioned above didn't happen on such a highway, but out in the nowhere
> after the two gliders both had happily cruised along on a straight track
> for several minutes (as the logger file showed), until they happened to
> be in the same place at the same time. Again just my purely personal,
> anectotical and irrelevant experience.
>
> Back to the topic: I'm convinced that all three would still be alive had
> FLARM already existed.

OK, that's a reasonable attitude, then. However, remember the
Social Scientist's creed: "The plural of anecdote is not data!"

The situation in the UK is that glider traffic is constrained into
class G
areas by low level class A, B, or C airline flyways. In the US, most
longer-distance (i.e. jets) airline traffic is over FL180 in class A,
and most
shorter-distance (i.e. turboprop) airline traffic is at lower
altitudes in class E.
Most GA traffic (except the high end corporate and charter stuff)
mingles
with everyone else in class E. Class B, C, and D is used to actively
control
the airspace around terminals (decreasing busyness goes with
decreasing
control levels).

Therefore, in the US glider cross country is more or less possible in
random directions, as constrained by local conditions (e.g. where I
fly
there are two class C complexes to the North and South of us, so we
usually fly to the W-NW or SE-NE). The glider traffic we see is
usually
our buddies from the same or a nearby club. Nearby usually means
50-100
miles where I've flown.

-- Matt

Eric Greenwell[_4_]

October 27th 10, 08:40 PM

On 10/27/2010 6:06 AM, Mike Schumann wrote:
>
> There's a difference between flying in high density VFR environments
> and close quarters flying. Flying in the pattern at a very busy GA
> airport is not nearly as challenging as flying in a gaggle with
> numerous other gliders.
It's hard to put numbers on this, because the particular situation can
be important in determining the risk, but I'm comfortable stating this:

"That's not true for me, as I am much more accustomed to gaggle flying
than flying at or near very busy GA airports, and I'm more comfortable
in the gaggle with numerous other gliders."

--

Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

Ramy

October 27th 10, 08:43 PM

On Oct 27, 10:39*am, John Smith > wrote:
> Bruce Hoult wrote:
> > What do you consider dangerous in cross country flying?
>
> I've lost three friends by midairs during leisure cross country flying
> but none during competition flying (all in Pre-FLARM-age). That's just
> my purely personal, anectotcal and irrelevant statistics.
>
> Where I fly, there are "glider highways" which can be pretty crowded on
> thermally active weekends. With the difference that competition pilots
> tend to be 100% awake, which cannot always be said of leisure pilots on
> an 8 hour leisure flight. Interesting is that one of the midairs
> mentioned above didn't happen on such a highway, but out in the nowhere
> after the two gliders both had happily cruised along on a straight track
> for several minutes (as the logger file showed), until they happened to
> be in the same place at the same time. Again just my purely personal,
> anectotical and irrelevant experience.
>
> Back to the topic: I'm convinced that all three would still be alive had
> FLARM already existed.

I think these examples reinforces the notion that PowerFlarm should be
installed by all pilots and not just competition pilots.
And I am glad to report that many pilots in my area (Region 11)
already per ordered the powerflarm even though most of them are not
flying in contest.

Ramy

Eric Greenwell[_4_]

October 27th 10, 08:48 PM

On 10/27/2010 7:20 AM, wrote:
>> in "awareness mode", of course a led will indicate where the closer
>> glider is, but still alarms will only be triggered when a deviation
>> makes the collision a real possibility.
>>
>> aldo cernezzi
>>
> Since the GPS accuracy is probably much poorer than 10 feet, when a
> glider comes within 10 feet, I figure the FLARM should consider that a
> collision, no?
I don't know what Flarm does in that case, but my guess is the
*relative* accuracy is much better than the *absolute* accuracy. If
that's true, then each glider might have position errors of much more
than 10 feet, but they'll have nearly the same errors, giving a more
accurate separation distance.

Maybe someone more familiar with GPS in this situation can jump in here
and tell us?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

David Smith[_3_]

October 27th 10, 10:06 PM

Having used Flarm for 2 years I have to agree, it is most effective in a
low density situation that is X/C and ridge flying which is what it was
designed for. Glider Highways where you are likely to meet another going
in the opposite direction at the same level Flarm will give you plenty of
warning. Almost all 95% + aircraft that I see at the same level are
gliders and if they all had Flarm that would please me. I am not sure how
useful the ADS and Transponder features will be, conflict with other
aircraft is thankfully unusual but if it picks up one power pilot with his
"head in the office" it will be worthwhile.

Dave

At 19:43 27 October 2010, Ramy wrote:
>On Oct 27, 10:39=A0am, John Smith wrote:
>> Bruce Hoult wrote:
>> > What do you consider dangerous in cross country flying?
>>
>> I've lost three friends by midairs during leisure cross country
flying
>> but none during competition flying (all in Pre-FLARM-age). That's
just
>> my purely personal, anectotcal and irrelevant statistics.
>>
>> Where I fly, there are "glider highways" which can be pretty crowded
on
>> thermally active weekends. With the difference that competition pilots
>> tend to be 100% awake, which cannot always be said of leisure pilots
on
>> an 8 hour leisure flight. Interesting is that one of the midairs
>> mentioned above didn't happen on such a highway, but out in the
nowhere
>> after the two gliders both had happily cruised along on a straight
track
>> for several minutes (as the logger file showed), until they happened
to
>> be in the same place at the same time. Again just my purely personal,
>> anectotical and irrelevant experience.
>>
>> Back to the topic: I'm convinced that all three would still be alive
had
>> FLARM already existed.
>
>I think these examples reinforces the notion that PowerFlarm should be
>installed by all pilots and not just competition pilots.
>And I am glad to report that many pilots in my area (Region 11)
>already per ordered the powerflarm even though most of them are not
>flying in contest.
>
>Ramy
>

David Smith[_3_]

October 27th 10, 10:06 PM

Mike Schumann

October 28th 10, 01:33 AM

On 10/27/2010 3:48 PM, Eric Greenwell wrote:
> On 10/27/2010 7:20 AM, wrote:
>>> in "awareness mode", of course a led will indicate where the closer
>>> glider is, but still alarms will only be triggered when a deviation
>>> makes the collision a real possibility.
>>>
>>> aldo cernezzi
>> Since the GPS accuracy is probably much poorer than 10 feet, when a
>> glider comes within 10 feet, I figure the FLARM should consider that a
>> collision, no?
> I don't know what Flarm does in that case, but my guess is the
> *relative* accuracy is much better than the *absolute* accuracy. If
> that's true, then each glider might have position errors of much more
> than 10 feet, but they'll have nearly the same errors, giving a more
> accurate separation distance.
>
> Maybe someone more familiar with GPS in this situation can jump in here
> and tell us?
>
Even if the relative GPS position computed by each glider has 0 error,
you still have the problem that at 50 Knots, each aircraft is moving ~
75 ft / second. With FLARM (or ADS-B) only transmitting positions every
second, you can't rely on these technologies to protect you from random
course changes that the systems can't possibly predict, if you are in
close proximity.

--
Mike Schumann

Eric Greenwell[_4_]

October 28th 10, 04:16 AM

On 10/27/2010 5:33 PM, Mike Schumann wrote:
> On 10/27/2010 3:48 PM, Eric Greenwell wrote:
>> On 10/27/2010 7:20 AM, wrote:
>>>> in "awareness mode", of course a led will indicate where the closer
>>>> glider is, but still alarms will only be triggered when a deviation
>>>> makes the collision a real possibility.
>>>>
>>>> aldo cernezzi
>>> Since the GPS accuracy is probably much poorer than 10 feet, when a
>>> glider comes within 10 feet, I figure the FLARM should consider that a
>>> collision, no?
>> I don't know what Flarm does in that case, but my guess is the
>> *relative* accuracy is much better than the *absolute* accuracy. If
>> that's true, then each glider might have position errors of much more
>> than 10 feet, but they'll have nearly the same errors, giving a more
>> accurate separation distance.
>>
>> Maybe someone more familiar with GPS in this situation can jump in here
>> and tell us?
>>
> Even if the relative GPS position computed by each glider has 0 error,
> you still have the problem that at 50 Knots, each aircraft is moving ~
> 75 ft / second. With FLARM (or ADS-B) only transmitting positions
> every second, you can't rely on these technologies to protect you from
> random course changes that the systems can't possibly predict, if you
> are in close proximity.
FLARM does more than transmit positions: it transmits the projected path
of it's glider. Here's what I understand will happen: when the pilot
makes a course change, a new path is calculated and compared to the
paths Flarm has received from nearby gliders. If this new path puts it
on a collision course with any of them, the pilot is warned
"immediately", meaning it does not have to wait one second. The new path
will be transmitted within one second, so the nearby gliders can update
the other glider's path in their database. It might actually be more
sophisticated than that, such as transmitting a new path sooner if the
amount of change is "large", but I don't know what the algorithms are.

This projected path is a key element to the system working properly.
Without it, each FLARM unit would have to calculate the path of every
nearby glider; with it, each unit only has to calculate one path - it's
own. Potentially, it could be using a much higher position rate than
once a second to calculate it's projected path. In any case, the result
is much better than you might think for a system that transmits once a
second.

Does ADS-B transmit a projected path, or just position?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

Andy[_10_]

October 28th 10, 08:11 AM

On Oct 27, 8:16*pm, Eric Greenwell > wrote:
> On 10/27/2010 5:33 PM, Mike Schumann wrote:
>
> > On 10/27/2010 3:48 PM, Eric Greenwell wrote:
> >> On 10/27/2010 7:20 AM, wrote:
> >>>> in "awareness mode", of course a led will indicate where the closer
> >>>> glider is, but still alarms will only be triggered when a deviation
> >>>> makes the collision a real possibility.
>
> >>>> aldo cernezzi
> >>> Since the GPS accuracy is probably much poorer than 10 feet, when a
> >>> glider comes within 10 feet, I figure the FLARM should consider that a
> >>> collision, no?
> >> I don't know what Flarm does in that case, but my guess is the
> >> *relative* accuracy is much better than the *absolute* accuracy. If
> >> that's true, then each glider might have position errors of much more
> >> than 10 feet, but they'll have nearly the same errors, giving a more
> >> accurate separation distance.
>
> >> Maybe someone more familiar with GPS in this situation can jump in here
> >> and tell us?
>
> > Even if the relative GPS position computed by each glider has 0 error,
> > you still have the problem that at 50 Knots, each aircraft is moving ~
> > 75 ft / second. *With FLARM (or ADS-B) only transmitting positions
> > every second, you can't rely on these technologies to protect you from
> > random course changes that the systems can't possibly predict, if you
> > are in close proximity.
>
> FLARM does more than transmit positions: it transmits the projected path
> of it's glider. Here's what I understand will happen: when the pilot
> makes a course change, a new path is calculated and compared to the
> paths Flarm has received from nearby gliders. If this new path puts it
> on a collision course with any of them, the pilot is warned
> "immediately", meaning it does not have to wait one second. The new path
> will be transmitted within one second, so the nearby gliders can update
> the other glider's path in their database. It might actually be more
> sophisticated than that, such as transmitting a new path sooner if the
> amount of change is "large", but I don't know what the algorithms are.
>
> This projected path is a key element to the system working properly.
> Without it, each FLARM unit would have to calculate the path of every
> nearby glider; with it, each unit only has to calculate one path - it's
> own. Potentially, it could be using a much higher position rate than
> once a second to calculate it's projected path. In any case, the result
> is much better than you might think for a system that transmits once a
> second.
>
> Does ADS-B transmit a projected path, or just position?
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

That's my understanding as well - the Flarm algorithm looks at a range
of potential paths that the glider might maneuver to and calculates
potential collisions on the basis of all potential paths within that
maneuvering envelope. I expect within a couple of seconds the path
assumes a fair amount of potential maneuvering while over a longer
period of time it would limit extreme maneuvering assumptions to be
closer to an extrapolation of the current path/turn rate. Because it
understands your trun rate it works well in thermals.

I have not heard anything about similar capabilities for ADS-B and I
am confident that it doesn't extrapolate with a glider performance
envelope in mind, since it isn't designed explicitly for gliders. I
would think ADS-B would be particularly challenged in predicting
likely collisions in thermals - much more so than Flarm.

9B

Andreas Maurer

October 28th 10, 02:47 PM

On Tue, 26 Oct 2010 18:03:50 -0700 (PDT), John Cochrane
> wrote:

>"Idiot" is perhaps a bit strong, and I may have been hasty in applying
>it to a fellow pilot. On the other hand, he did pass 10-20 feet over
>the top of my glider in a large gaggle.

One pilot who I know very well told me that during a WGC when he was
competing for the first place (he was in the lead), one very-well
known competitor flew maneuvres that this pilot could only classify as
attempts to produce near-misses. Within half an hour they had two
near-misses with less than fifteen feet, both provoked by the same
pilot.

Then the pilot in question lost his nerves and broke off the flight.
The attacking pilot won the WGC.

Andreas

Brian[_1_]

October 28th 10, 02:53 PM

On Oct 28, 1:11*am, Andy > wrote:
> On Oct 27, 8:16*pm, Eric Greenwell > wrote:
>
>
>
>
>
> > On 10/27/2010 5:33 PM, Mike Schumann wrote:
>
> > > On 10/27/2010 3:48 PM, Eric Greenwell wrote:
> > >> On 10/27/2010 7:20 AM, wrote:
> > >>>> in "awareness mode", of course a led will indicate where the closer
> > >>>> glider is, but still alarms will only be triggered when a deviation
> > >>>> makes the collision a real possibility.
>
> > >>>> aldo cernezzi
> > >>> Since the GPS accuracy is probably much poorer than 10 feet, when a
> > >>> glider comes within 10 feet, I figure the FLARM should consider that a
> > >>> collision, no?
> > >> I don't know what Flarm does in that case, but my guess is the
> > >> *relative* accuracy is much better than the *absolute* accuracy. If
> > >> that's true, then each glider might have position errors of much more
> > >> than 10 feet, but they'll have nearly the same errors, giving a more
> > >> accurate separation distance.
>
> > >> Maybe someone more familiar with GPS in this situation can jump in here
> > >> and tell us?
>
> > > Even if the relative GPS position computed by each glider has 0 error,
> > > you still have the problem that at 50 Knots, each aircraft is moving ~
> > > 75 ft / second. *With FLARM (or ADS-B) only transmitting positions
> > > every second, you can't rely on these technologies to protect you from
> > > random course changes that the systems can't possibly predict, if you
> > > are in close proximity.
>
> > FLARM does more than transmit positions: it transmits the projected path
> > of it's glider. Here's what I understand will happen: when the pilot
> > makes a course change, a new path is calculated and compared to the
> > paths Flarm has received from nearby gliders. If this new path puts it
> > on a collision course with any of them, the pilot is warned
> > "immediately", meaning it does not have to wait one second. The new path
> > will be transmitted within one second, so the nearby gliders can update
> > the other glider's path in their database. It might actually be more
> > sophisticated than that, such as transmitting a new path sooner if the
> > amount of change is "large", but I don't know what the algorithms are.
>
> > This projected path is a key element to the system working properly.
> > Without it, each FLARM unit would have to calculate the path of every
> > nearby glider; with it, each unit only has to calculate one path - it's
> > own. Potentially, it could be using a much higher position rate than
> > once a second to calculate it's projected path. In any case, the result
> > is much better than you might think for a system that transmits once a
> > second.
>
> > Does ADS-B transmit a projected path, or just position?
>
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
> > - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz
>
> That's my understanding as well - the Flarm algorithm looks at a range
> of potential paths that the glider might maneuver to and calculates
> potential collisions on the basis of all potential paths within that
> maneuvering envelope. *I expect within a couple of seconds the path
> assumes a fair amount of potential maneuvering while over a longer
> period of time it would limit extreme maneuvering assumptions to be
> closer to an extrapolation of the current path/turn rate. Because it
> understands your trun rate it works well in thermals.
>
> I have not heard anything about similar capabilities for ADS-B and I
> am confident that it doesn't extrapolate with a glider performance
> envelope in mind, since it isn't designed explicitly for gliders. I
> would think ADS-B would be particularly challenged in predicting
> likely collisions in thermals - much more so than Flarm.
>
> 9B- Hide quoted text -
>
> - Show quoted text -

I hadn't really considered how the projected flight path system works
before. But after thinking about it for a bit it has a lot of
potentional. How much the Flarm actually uses I do not know. But it
would be possible for the Flarm to actually learn the possible flight
paths for a given glider and dynamically adjust it's algorithm for
where the glider might be able to go from that. Even without that I
can see that gliders could get very close but have potential flight
paths that would make colliding impossible and as a result would not
create a collision alarm.

Brian

Mike Schumann

October 28th 10, 03:29 PM

On 10/27/2010 11:16 PM, Eric Greenwell wrote:
> On 10/27/2010 5:33 PM, Mike Schumann wrote:
>> On 10/27/2010 3:48 PM, Eric Greenwell wrote:
>>> On 10/27/2010 7:20 AM, wrote:
>>>>> in "awareness mode", of course a led will indicate where the closer
>>>>> glider is, but still alarms will only be triggered when a deviation
>>>>> makes the collision a real possibility.
>>>>>
>>>>> aldo cernezzi
>>>> Since the GPS accuracy is probably much poorer than 10 feet, when a
>>>> glider comes within 10 feet, I figure the FLARM should consider that a
>>>> collision, no?
>>> I don't know what Flarm does in that case, but my guess is the
>>> *relative* accuracy is much better than the *absolute* accuracy. If
>>> that's true, then each glider might have position errors of much more
>>> than 10 feet, but they'll have nearly the same errors, giving a more
>>> accurate separation distance.
>>>
>>> Maybe someone more familiar with GPS in this situation can jump in here
>>> and tell us?
>>>
>> Even if the relative GPS position computed by each glider has 0 error,
>> you still have the problem that at 50 Knots, each aircraft is moving ~
>> 75 ft / second. With FLARM (or ADS-B) only transmitting positions
>> every second, you can't rely on these technologies to protect you from
>> random course changes that the systems can't possibly predict, if you
>> are in close proximity.
> FLARM does more than transmit positions: it transmits the projected path
> of it's glider. Here's what I understand will happen: when the pilot
> makes a course change, a new path is calculated and compared to the
> paths Flarm has received from nearby gliders. If this new path puts it
> on a collision course with any of them, the pilot is warned
> "immediately", meaning it does not have to wait one second. The new path
> will be transmitted within one second, so the nearby gliders can update
> the other glider's path in their database. It might actually be more
> sophisticated than that, such as transmitting a new path sooner if the
> amount of change is "large", but I don't know what the algorithms are.
>
> This projected path is a key element to the system working properly.
> Without it, each FLARM unit would have to calculate the path of every
> nearby glider; with it, each unit only has to calculate one path - it's
> own. Potentially, it could be using a much higher position rate than
> once a second to calculate it's projected path. In any case, the result
> is much better than you might think for a system that transmits once a
> second.
>
> Does ADS-B transmit a projected path, or just position?
>
I'm not an expert on either FLARM or ADS-B. I believe that ADS-B
currently only transmits absolute position. Future enhancements might
transmit trajectory, which would be most useful for aircraft with Flight
Management Systems where the trajectory is well defined and could be
used by the ATC system for airspace management.

Regardless of whether or not the trajectory is transmitted, a
sophisticated receiving system (either FLARM or ADS-B based), can
remember each aircraft's position data and compute it's current
trajectory. While a glider might be moving 75 ft / sec, this is
obviously in a relatively forward direction.

Neither the transmitting nor the receiving FLARM or ADS-B system can
predict an abrupt change in course that a pilot flying manually might
command. However, every aircraft has physical limits on roll rates,
etc. that restrain the potential change in direction that can occur
within the one second update interval of these systems. As a result,
the systems can, theoretically, compute a pear shaped threat envelope
for each aircraft and limit collision warnings to those situations where
these envelopes intersect.

It would be interesting to get more detailed information on the exact
algorithms that FLARM uses in it's collision threat analysis and compare
this to the actual unit performance in situations where gliders are
flying at close distances in formation or in gaggles. This could also
help pilots understand the limitations of these systems so they don't
develop a false sense of security in situations where these systems are
not reliable.

--
Mike Schumann

Andreas Maurer

October 28th 10, 03:32 PM

On Thu, 28 Oct 2010 06:53:27 -0700 (PDT), Brian >
wrote:

>I hadn't really considered how the projected flight path system works
>before. But after thinking about it for a bit it has a lot of
>potentional. How much the Flarm actually uses I do not know.

Flarm uses ONLY projected flight paths to calculate a collision
probability.

>Even without that I
>can see that gliders could get very close but have potential flight
>paths that would make colliding impossible and as a result would not
>create a collision alarm.

This is exactly how Flarm works.
Flarm doesn't care about distances - as long as Flarm doesn't detect a
potential collision cource, you can fly very close to each other
without getting a warning - even if you are circling.

Andreas

Andy[_10_]

October 28th 10, 04:47 PM

On Oct 28, 7:32*am, Andreas Maurer > wrote:
> On Thu, 28 Oct 2010 06:53:27 -0700 (PDT), Brian >
> wrote:
>
> >I hadn't really considered how the projected flight path system works
> >before. But after thinking about it for a bit it has a lot of
> >potentional. How much the Flarm actually uses I do not know.
>
> Flarm uses ONLY projected flight paths to calculate a collision
> probability.
>
> >Even without that I
> >can see that gliders could get very close but have potential flight
> >paths that would make colliding impossible and as a result would not
> >create a collision alarm.
>
> This is exactly how Flarm works.
> Flarm doesn't care about distances - as long as Flarm doesn't detect a
> potential collision cource, you can fly very close to each other
> without getting a warning - even if you are circling.
>
> Andreas

I think that's the secret for how you make it useful in thermals - if
the system knows you are circling it can do a better job predicting
your curved flight path and potential threats along that path. I
presume that if you assume the full maneuvering envelope of each
glider you'd generate a lot of warnings, so it would make sense to
assume something more limited that strikes a balance between false
positive warnings and missing potential maneuvers that could create a
threat with little advanced notice. Think of a glider pulling up into
a thermal as a good example. I assume that Flarm does all this based
on the following explanation where an expanding projected flight path
envelope is depicted:

http://www.gliderpilot.org/Flarm-WhatDoesItDo

As to ADS-B - without some algorithm for projecting flight paths the
only warning you can realistically generate is a proximity warning.
Even warning only for declining separation distance is a crude form of
relative path prediction, just not a very useful one - particularly
for glider operations with multiple targets and circling flight.

9B

Eric Greenwell[_4_]

October 28th 10, 07:14 PM

On 10/28/2010 7:29 AM, Mike Schumann wrote:
> On 10/27/2010 11:16 PM, Eric Greenwell wrote:
>>
>>
>> This projected path is a key element to the system working properly.
>> Without it, each FLARM unit would have to calculate the path of every
>> nearby glider; with it, each unit only has to calculate one path - it's
>> own. Potentially, it could be using a much higher position rate than
>> once a second to calculate it's projected path. In any case, the result
>> is much better than you might think for a system that transmits once a
>> second.
>>
>> Does ADS-B transmit a projected path, or just position?
>>
> I'm not an expert on either FLARM or ADS-B. I believe that ADS-B
> currently only transmits absolute position. Future enhancements might
> transmit trajectory, which would be most useful for aircraft with
> Flight Management Systems where the trajectory is well defined and
> could be used by the ATC system for airspace management.
>
> Regardless of whether or not the trajectory is transmitted, a
> sophisticated receiving system (either FLARM or ADS-B based), can
> remember each aircraft's position data and compute it's current
> trajectory. While a glider might be moving 75 ft / sec, this is
> obviously in a relatively forward direction.
You may be underestimating the value of transmitting the projected path.
When another glider is first detected, your unit has only one position
report and can not determine the flight path from that single point, and
it will take several more precious seconds to determine the flight path
of the potential threat; however, because the projected path is
transmitted every second, your unit immediately knows it.
>
> Neither the transmitting nor the receiving FLARM or ADS-B system can
> predict an abrupt change in course that a pilot flying manually might
> command. However, every aircraft has physical limits on roll rates,
> etc. that restrain the potential change in direction that can occur
> within the one second update interval of these systems. As a result,
> the systems can, theoretically, compute a pear shaped threat envelope
> for each aircraft and limit collision warnings to those situations
> where these envelopes intersect.
>
> It would be interesting to get more detailed information on the exact
> algorithms that FLARM uses in it's collision threat analysis and
> compare this to the actual unit performance in situations where
> gliders are flying at close distances in formation or in gaggles.
> This could also help pilots understand the limitations of these
> systems so they don't develop a false sense of security in situations
> where these systems are not reliable.

I'm sure the developers have tested their algorithms with thousands of
simulations using IGC files from gliders in many situations. The Parowan
accident simulation at

http://www.gliderpilot.org/Flarm-ParowanMidairSimulation

shows what can be done. It would be interesting, informative, and
entertaining if there was a website or application that would let us run
IGC files we select in a simulation like this. I'm curious about how
Flarm would react in a few situations I've encountered. Doing
simulations on a pilot's own files might be more persuasive of the value
of Flarm than even the most well-written explanations, and much more
easily understood than the algorithms themselves.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

Mike Schumann

October 28th 10, 07:32 PM

On 10/28/2010 2:14 PM, Eric Greenwell wrote:
> On 10/28/2010 7:29 AM, Mike Schumann wrote:
>> On 10/27/2010 11:16 PM, Eric Greenwell wrote:
>>>
>>>
>>> This projected path is a key element to the system working properly.
>>> Without it, each FLARM unit would have to calculate the path of every
>>> nearby glider; with it, each unit only has to calculate one path - it's
>>> own. Potentially, it could be using a much higher position rate than
>>> once a second to calculate it's projected path. In any case, the result
>>> is much better than you might think for a system that transmits once a
>>> second.
>>>
>>> Does ADS-B transmit a projected path, or just position?
>>>
>> I'm not an expert on either FLARM or ADS-B. I believe that ADS-B
>> currently only transmits absolute position. Future enhancements might
>> transmit trajectory, which would be most useful for aircraft with
>> Flight Management Systems where the trajectory is well defined and
>> could be used by the ATC system for airspace management.
>>
>> Regardless of whether or not the trajectory is transmitted, a
>> sophisticated receiving system (either FLARM or ADS-B based), can
>> remember each aircraft's position data and compute it's current
>> trajectory. While a glider might be moving 75 ft / sec, this is
>> obviously in a relatively forward direction.
> You may be underestimating the value of transmitting the projected path.
> When another glider is first detected, your unit has only one position
> report and can not determine the flight path from that single point, and
> it will take several more precious seconds to determine the flight path
> of the potential threat; however, because the projected path is
> transmitted every second, your unit immediately knows it.
>>
>> Neither the transmitting nor the receiving FLARM or ADS-B system can
>> predict an abrupt change in course that a pilot flying manually might
>> command. However, every aircraft has physical limits on roll rates,
>> etc. that restrain the potential change in direction that can occur
>> within the one second update interval of these systems. As a result,
>> the systems can, theoretically, compute a pear shaped threat envelope
>> for each aircraft and limit collision warnings to those situations
>> where these envelopes intersect.
>>
>> It would be interesting to get more detailed information on the exact
>> algorithms that FLARM uses in it's collision threat analysis and
>> compare this to the actual unit performance in situations where
>> gliders are flying at close distances in formation or in gaggles. This
>> could also help pilots understand the limitations of these systems so
>> they don't develop a false sense of security in situations where these
>> systems are not reliable.
>
> I'm sure the developers have tested their algorithms with thousands of
> simulations using IGC files from gliders in many situations. The Parowan
> accident simulation at
>
> http://www.gliderpilot.org/Flarm-ParowanMidairSimulation
>
> shows what can be done. It would be interesting, informative, and
> entertaining if there was a website or application that would let us run
> IGC files we select in a simulation like this. I'm curious about how
> Flarm would react in a few situations I've encountered. Doing
> simulations on a pilot's own files might be more persuasive of the value
> of Flarm than even the most well-written explanations, and much more
> easily understood than the algorithms themselves.
>

There's no question that FLARM or ADS-B based systems could have easily
prevented the Parowan mid-air. My question is how much you can rely on
this type of equipment to accurately warn you of collisions when you are
flying in gaggles.

Obviously knowing the relative position of other gliders in the gaggle
is helpful. I would be very skeptical, however, of putting my faith in
FLARM or any other system to accurately warn me of a collision with
another glider that was in the same thermal, near my altitude, that was
in my blind spot.

Transmitting the project path of the aircraft is really only beneficial
if the equipment on board the transmitting aircraft has some added
information that is not available to the receiver on the transmitting
aircraft's intent.

With both FLARM and ADS-B systems, the initial visibility of the other
aircraft occurs way before there is any collision threat, so the
receiver should have no difficulty computing the project path of the
other aircraft. ADS-B actually transmits the category of aircraft (i.e.
glider, balloon, etc...) so the receiver can get a pretty good hint on
the type of maneuvers that can be expected.

--
Mike Schumann

John Smith

October 28th 10, 07:45 PM

Eric Greenwell wrote:
> On 10/28/2010 7:29 AM, Mike Schumann wrote:

>> It would be interesting to get more detailed information on the exact
>> algorithms that FLARM uses in it's collision threat analysis

I tend to assume that if there is one thing that the developers want to
keep, then it's this algorithm. ;-)

But from real life experience, it seem's to work pretty well.

> It would be interesting, informative, andentertaining if there was
> a website or application that would let us runIGC files we select
> in a simulation like this.

Entertaining... well... but educative indeed. And it would provide the
FLARM developers with a huge test crew for free.

Darryl Ramm

October 28th 10, 08:29 PM

On Oct 28, 8:47 am, Andy > wrote:
> On Oct 28, 7:32 am, Andreas Maurer > wrote:
>
>
>
> > On Thu, 28 Oct 2010 06:53:27 -0700 (PDT), Brian >
> > wrote:
>
> > >I hadn't really considered how the projected flight path system works
> > >before. But after thinking about it for a bit it has a lot of
> > >potentional. How much the Flarm actually uses I do not know.
>
> > Flarm uses ONLY projected flight paths to calculate a collision
> > probability.
>
> > >Even without that I
> > >can see that gliders could get very close but have potential flight
> > >paths that would make colliding impossible and as a result would not
> > >create a collision alarm.
>
> > This is exactly how Flarm works.
> > Flarm doesn't care about distances - as long as Flarm doesn't detect a
> > potential collision cource, you can fly very close to each other
> > without getting a warning - even if you are circling.
>
> > Andreas
>
> I think that's the secret for how you make it useful in thermals - if
> the system knows you are circling it can do a better job predicting
> your curved flight path and potential threats along that path. I
> presume that if you assume the full maneuvering envelope of each
> glider you'd generate a lot of warnings, so it would make sense to
> assume something more limited that strikes a balance between false
> positive warnings and missing potential maneuvers that could create a
> threat with little advanced notice. Think of a glider pulling up into
> a thermal as a good example. I assume that Flarm does all this based
> on the following explanation where an expanding projected flight path
> envelope is depicted:
>
> http://www.gliderpilot.org/Flarm-WhatDoesItDo
>
> As to ADS-B - without some algorithm for projecting flight paths the
> only warning you can realistically generate is a proximity warning.
> Even warning only for declining separation distance is a crude form of
> relative path prediction, just not a very useful one - particularly
> for glider operations with multiple targets and circling flight.
>
> 9B

Just to give a flavor ADS-B data-out systems as mandated for 2020 in
the USA for power aircraft (basically where a transponder is required
today) will put out the following data

Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
Aircraft callsign/flight number (not required for VFR flight)
Time of applicability
GPS Lattitude
GPS Longitude
GPS altitude
Airborne/on-surface status
Northbound ground velocity component while airborne (from GPS)
Eastbound ground velocity component while airborne (from GPS)
Heading while on the surface
Ground speed while on the surface
Pressure altitude
Vertical rate (may be pressure or GPS based)
GPS uncertainty/integrity (which needs information form a fancy TSO-
C145 class WAAS GPS)
Ident (equivalent to transponder ident/SPI)
Distress/Emergency status
ADS-B data-in/display capability
TCAS equipage/status

This is a simplified list and there is various other status/validity
data as well. There is also the concept in ADS-B messages of an
estimated position, and even estimated velocity. But AFAIK this is not
intended for fancy manoeuvrings predictions - it is more intended to
allow different parts of the ADS-B infrastructure to project position
or velocity updated to a single time of applicability. There is space
for future expansion and as an example there is long-term work
underway to look at an ADS-B based replacement for TCAS that could
well utilize extra data transmission than that above, but think well
post 2020 for this to actually happen. My brain hurts enough thinking
about ADS-B as is.

---

BTW my suspicion is given that the FAA currently requires a STC for
any installation for ADS-B data out that it is currently not possible
to install any ADS-B data-out system in the USA in any certified
aircraft (including gliders) that only meets a subset of the 2020
mandate requirements (ie. does not include all the stuff above). Which
I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
Experimental aircraft are another question since an STC cannot apply
to them. This STC restriction hopefully is short-term as its is going
to have a chilling effect on ADS-B data-out adoption in general
aviation and gliders. Besides some more complex issues you can start
to see even simple installation concerns that are probably causing
this current STC requirement, such as squat switch/or other on-ground
detection, needs to have a single squawk code and ident button across
any installed transponder(s) and ADS-B data-out devices, ability to
transmit a distress/emergency code, ability to turn off the ADS-B
transmissions if requested, etc.

Darryl

Eric Greenwell[_4_]

October 28th 10, 08:36 PM

On 10/28/2010 11:32 AM, Mike Schumann wrote:
>
>
> There's no question that FLARM or ADS-B based systems could have
> easily prevented the Parowan mid-air. My question is how much you can
> rely on this type of equipment to accurately warn you of collisions
> when you are flying in gaggles.
>
> Obviously knowing the relative position of other gliders in the gaggle
> is helpful. I would be very skeptical, however, of putting my faith
> in FLARM or any other system to accurately warn me of a collision with
> another glider that was in the same thermal, near my altitude, that
> was in my blind spot.
This situation is addressed at

http://www.gliderpilot.org/FlarmFlightSituationsandPerformance

where it states that the human eye is better than Flarm. I don't think
anyone has claimed Flarm is better in every possible situation, and
users and Flarm itself repeatedly state you must still look outside to
have the best protection; however, I believe Flarm will indicate there
is a glider behind you, something a pilot might not always be aware of,
so it still has value in this situation.
>
> Transmitting the project path of the aircraft is really only
> beneficial if the equipment on board the transmitting aircraft has
> some added information that is not available to the receiver on the
> transmitting aircraft's intent.
>
> With both FLARM and ADS-B systems, the initial visibility of the other
> aircraft occurs way before there is any collision threat, so the
> receiver should have no difficulty computing the project path of the
> other aircraft. ADS-B actually transmits the category of aircraft
> (i.e. glider, balloon, etc...) so the receiver can get a pretty good
> hint on the type of maneuvers that can be expected.
I can think of three situations where the time involved can be reduced:

1) two gliders approaching head on. At 100 knots each - a 200 knot
closing speed - that's only 18 seconds or so to collision. How many
seconds of warning do you lose while collecting enough points to make a
good estimate of the projected paths - 5 seconds, 10 seconds? I don't
know, but I'd prefer to know sooner than later.

2) Ridge or mountain flying, where the transmissions are blocked by the
terrain. Once they round the corner of the ridge, there may not be
enough time to calculate a projected path.

3) shortened range due to signal blockage by the wings or fuselage.

--

Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

John Smith

October 28th 10, 08:39 PM

Mike Schumann wrote:
> My question is how much you can rely on
> this type of equipment to accurately warn you of collisions when you are
> flying in gaggles.

In gaggles: Not at all. Period. Simply not possible - and not
necessairy, either.

Wayne Paul

October 28th 10, 09:40 PM

"Darryl Ramm" > wrote in message ...
> On Oct 28, 8:47 am, Andy > wrote:
>>
> Just to give a flavor ADS-B data-out systems as mandated for 2020 in
> the USA for power aircraft (basically where a transponder is required
> today) will put out the following data
>
> Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
> Aircraft callsign/flight number (not required for VFR flight)
> Time of applicability
> GPS Lattitude
> GPS Longitude
> GPS altitude
> Airborne/on-surface status
> Northbound ground velocity component while airborne (from GPS)
> Eastbound ground velocity component while airborne (from GPS)
> Heading while on the surface
> Ground speed while on the surface
> Pressure altitude
> Vertical rate (may be pressure or GPS based)
> GPS uncertainty/integrity (which needs information form a fancy TSO-
> C145 class WAAS GPS)
> Ident (equivalent to transponder ident/SPI)
> Distress/Emergency status
> ADS-B data-in/display capability
> TCAS equipage/status
>
> This is a simplified list and there is various other status/validity
> data as well. There is also the concept in ADS-B messages of an
> estimated position, and even estimated velocity. But AFAIK this is not
> intended for fancy manoeuvrings predictions - it is more intended to
> allow different parts of the ADS-B infrastructure to project position
> or velocity updated to a single time of applicability. There is space
> for future expansion and as an example there is long-term work
> underway to look at an ADS-B based replacement for TCAS that could
> well utilize extra data transmission than that above, but think well
> post 2020 for this to actually happen. My brain hurts enough thinking
> about ADS-B as is.
>
> ---
>
> BTW my suspicion is given that the FAA currently requires a STC for
> any installation for ADS-B data out that it is currently not possible
> to install any ADS-B data-out system in the USA in any certified
> aircraft (including gliders) that only meets a subset of the 2020
> mandate requirements (ie. does not include all the stuff above). Which
> I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
> C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
> Experimental aircraft are another question since an STC cannot apply
> to them. This STC restriction hopefully is short-term as its is going
> to have a chilling effect on ADS-B data-out adoption in general
> aviation and gliders. Besides some more complex issues you can start
> to see even simple installation concerns that are probably causing
> this current STC requirement, such as squat switch/or other on-ground
> detection, needs to have a single squawk code and ident button across
> any installed transponder(s) and ADS-B data-out devices, ability to
> transmit a distress/emergency code, ability to turn off the ADS-B
> transmissions if requested, etc.
>
> Darryl

The following is not directed at any individual, it is simply an observation.

Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. It is data output sentences are fully compliant with NMEA 0183 ver 2.0. The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.
http://www8.garmin.com/support/pdf/NMEA_0183.pdf

As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.

Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.

Respectfully,
Wayne

SoaringXCellence

October 28th 10, 09:54 PM

On Oct 28, 1:40*pm, "Wayne Paul" > wrote:
> "Darryl Ramm" > wrote in ...
> > On Oct 28, 8:47 am, Andy > wrote:
>
> > Just to give a flavor ADS-B data-out systems as mandated for 2020 in
> > the USA for power aircraft (basically where a transponder is required
> > today) will put out the following data
>
> > Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
> > Aircraft callsign/flight number (not required for VFR flight)
> > Time of applicability
> > GPS Lattitude
> > GPS Longitude
> > GPS altitude
> > Airborne/on-surface status
> > Northbound ground velocity component while airborne (from GPS)
> > Eastbound ground velocity component while airborne (from GPS)
> > Heading while on the surface
> > Ground speed while on the surface
> > Pressure altitude
> > Vertical rate (may be pressure or GPS based)
> > GPS uncertainty/integrity (which needs information form a fancy TSO-
> > C145 class WAAS GPS)
> > Ident (equivalent to transponder ident/SPI)
> > Distress/Emergency status
> > ADS-B data-in/display capability
> > TCAS equipage/status
>
> > This is a simplified list and there is various other status/validity
> > data as well. There is also the concept in ADS-B messages of an
> > estimated position, and even estimated velocity. But AFAIK this is not
> > intended for fancy manoeuvrings predictions - it is more intended to
> > allow different parts of the ADS-B infrastructure to project position
> > or velocity updated to a single time of applicability. There is space
> > for future expansion and as an example there is long-term work
> > underway to look at an ADS-B based replacement for TCAS that could
> > well utilize extra data transmission than that above, but think well
> > post 2020 for this to actually happen. My brain hurts enough thinking
> > about ADS-B as is.
>
> > ---
>
> > BTW my suspicion is given that the FAA currently requires a STC for
> > any installation for ADS-B data out that it is currently not possible
> > to install any ADS-B data-out system in the USA in any certified
> > aircraft (including gliders) that only meets a subset of the 2020
> > mandate requirements (ie. does not include all the stuff above). Which
> > I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
> > C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
> > Experimental aircraft are another question since an STC cannot apply
> > to them. This STC restriction hopefully is short-term as its is going
> > to have a chilling effect on ADS-B data-out adoption in general
> > aviation and gliders. Besides some more complex issues you can start
> > to see even simple installation concerns that are probably causing
> > this current STC requirement, such as squat switch/or other on-ground
> > detection, needs to have a single squawk code and ident button across
> > any installed transponder(s) and ADS-B data-out devices, ability to
> > transmit a distress/emergency code, ability to turn off the ADS-B
> > transmissions if requested, etc.
>
> > Darryl
>
> The following is not directed at any individual, it is simply an observation.
>
> Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. *It is data output sentences are fully compliant with NMEA 0183 ver 2.0. *The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>
> As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>
> Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.
>
> Respectfully,
> Wayne

There have been several comment regarding the need for an STC to
install an ADS-B system in a certified aircraft.

This is not unlike the original situation with the installation of IFR
certified GPS systems, in the early 1990s. I was involved in several
installations and most of the concerns were about the placement of
antenna and the effect of spurious signals on navigation.

Today if you get an IFR GPS installed in an aircraft the manufacturer
has a detailed description of antenna placement, cable routing and
possible interaction. This data was collected during the earlier STC
period and as experience with more installations was gained, the FAA
changed the requirements from an STC to a 337, if installed in
compliance with the manufacturer's instructions.

I expect that the STC requirements for the ADS-B will follow the same
path over time.

Mike

Darryl Ramm

October 28th 10, 10:15 PM

On Oct 28, 1:54*pm, SoaringXCellence > wrote:
> On Oct 28, 1:40*pm, "Wayne Paul" > wrote:
>
>
>
> > "Darryl Ramm" > wrote in ...
> > > On Oct 28, 8:47 am, Andy > wrote:
>
> > > Just to give a flavor ADS-B data-out systems as mandated for 2020 in
> > > the USA for power aircraft (basically where a transponder is required
> > > today) will put out the following data
>
> > > Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
> > > Aircraft callsign/flight number (not required for VFR flight)
> > > Time of applicability
> > > GPS Lattitude
> > > GPS Longitude
> > > GPS altitude
> > > Airborne/on-surface status
> > > Northbound ground velocity component while airborne (from GPS)
> > > Eastbound ground velocity component while airborne (from GPS)
> > > Heading while on the surface
> > > Ground speed while on the surface
> > > Pressure altitude
> > > Vertical rate (may be pressure or GPS based)
> > > GPS uncertainty/integrity (which needs information form a fancy TSO-
> > > C145 class WAAS GPS)
> > > Ident (equivalent to transponder ident/SPI)
> > > Distress/Emergency status
> > > ADS-B data-in/display capability
> > > TCAS equipage/status
>
> > > This is a simplified list and there is various other status/validity
> > > data as well. There is also the concept in ADS-B messages of an
> > > estimated position, and even estimated velocity. But AFAIK this is not
> > > intended for fancy manoeuvrings predictions - it is more intended to
> > > allow different parts of the ADS-B infrastructure to project position
> > > or velocity updated to a single time of applicability. There is space
> > > for future expansion and as an example there is long-term work
> > > underway to look at an ADS-B based replacement for TCAS that could
> > > well utilize extra data transmission than that above, but think well
> > > post 2020 for this to actually happen. My brain hurts enough thinking
> > > about ADS-B as is.
>
> > > ---
>
> > > BTW my suspicion is given that the FAA currently requires a STC for
> > > any installation for ADS-B data out that it is currently not possible
> > > to install any ADS-B data-out system in the USA in any certified
> > > aircraft (including gliders) that only meets a subset of the 2020
> > > mandate requirements (ie. does not include all the stuff above). Which
> > > I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
> > > C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
> > > Experimental aircraft are another question since an STC cannot apply
> > > to them. This STC restriction hopefully is short-term as its is going
> > > to have a chilling effect on ADS-B data-out adoption in general
> > > aviation and gliders. Besides some more complex issues you can start
> > > to see even simple installation concerns that are probably causing
> > > this current STC requirement, such as squat switch/or other on-ground
> > > detection, needs to have a single squawk code and ident button across
> > > any installed transponder(s) and ADS-B data-out devices, ability to
> > > transmit a distress/emergency code, ability to turn off the ADS-B
> > > transmissions if requested, etc.
>
> > > Darryl
>
> > The following is not directed at any individual, it is simply an observation.
>
> > Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. *It is data output sentences are fully compliant with NMEA 0183 ver 2.0. *The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>
> > As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>
> > Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety..
>
> > Respectfully,
> > Wayne
>
> There have been several comment regarding the need for an STC to
> install an ADS-B system in a certified aircraft.
>
> This is not unlike the original situation with the installation of IFR
> certified GPS systems, in the early 1990s. *I was involved in several
> installations and most of the concerns were about the placement of
> antenna and the effect of spurious signals on navigation.
>
> Today if you get an IFR GPS installed in an aircraft the manufacturer
> has a detailed description of antenna placement, cable routing and
> possible interaction. *This data was collected during the earlier STC
> period and as experience with more installations was gained, the FAA
> changed the requirements from an STC to a 337, if installed in
> compliance with the manufacturer's instructions.
>
> I expect that the STC requirements for the ADS-B will follow the same
> path over time.
>
> Mike

Absolutely right (and antenna issues are one of the concerns with this
STC requirement as well). Its a matter of when the STC process
migrates to a 337/Field approval. Given the complexity of ADS-B I
wonder what the time frame will really be. And the FCC has stated that
clearly but the STC requirement still seems to have come as a bit of a
surprise to some developers--and maybe regulators where there are
questions if the cost of this was included in disclosures. I see no
way for now but for this to freeze a lot of adoption--but I suspect
from the FAA viewpoint it is needed. I do worry that smaller
manufacturers won't be able to develop many STCs and I am doubtful
you'll see folks willing to develop STCs for gliders. My purpose of
promoting the STC issue is just nobody seemed to be aware of it in
the glider community yet there are (a few) owners starting to look at
install of ADS-B data-out. Some of those owners have experimental
gliders and are in a better position. Those with certified gliders
need to have a discussion with vendors about STCs. In a practical
sense as well most vendors are busy finishing off their "-B" rev data-
out products (e.g. Garmin, Trig and others) and getting TSO approval
on those. And I see that as a gate to STC approval, but clearly they
could be overlapping TSO approval and STC development. And larger
companies beside having lots of STC approval experience may also be
able to leverage past ADS-B STC developed for trails, such as the
GOMEX ADS-B trials.

Darryl

Dave Nadler

October 28th 10, 11:14 PM

On Oct 28, 2:14*pm, Eric Greenwell > wrote:
> >> This projected path is a key element to the system working properly.
> >> Without it, each FLARM unit would have to calculate the path of every
> >> nearby glider; with it, each unit only has to calculate one path - it's
> >> own. Potentially, it could be using a much higher position rate than
> >> once a second to calculate it's projected path. In any case, the result
> >> is much better than you might think for a system that transmits once a
> >> second.
>
> ...
> You may be underestimating the value of transmitting the projected path.
> When another glider is first detected, your unit has only one position
> report and can not determine the flight path from that single point, and
> it will take several more precious seconds to determine the flight path
> of the potential threat; however, because the projected path is
> transmitted every second, your unit immediately knows it.
>
> > It would be interesting to get more detailed information on the exact
> > algorithms that FLARM uses in it's collision threat analysis and
> > compare this to the actual unit performance in situations where
> > gliders are flying at close distances in formation or in gaggles. *
> > This could also help pilots understand the limitations of these
> > systems so they don't develop a false sense of security in situations
> > where these systems are not reliable.
>
> I'm sure the developers have tested their algorithms with thousands of
> simulations using IGC files from gliders in many situations. The Parowan
> accident simulation at
>
> http://www.gliderpilot.org/Flarm-ParowanMidairSimulation
>
> shows what can be done. It would be interesting, informative, and
> entertaining if there was a website or application that would let us run
> IGC files we select in a simulation like this. I'm curious about how
> Flarm would react in a few situations I've encountered. Doing
> simulations on a pilot's own files might be more persuasive of the value
> of Flarm than even the most well-written explanations, and much more
> easily understood than the algorithms themselves.

If you watch the Parowan simulation carefully, you will see that
the collision alarm sounds BEFORE the straight-line trajectories
intersect. This is because one of the gliders is circling, and the
projected trajectory (circling) shows a collision SECONDS
before the straight-line trajectories intersect.

These additional seconds can be a life-saver.

Hope that helps clarify,
Best Regards, Dave "YO electric"

Dave Nadler

October 28th 10, 11:38 PM

On Oct 28, 4:54*pm, SoaringXCellence > wrote:
> On Oct 28, 1:40*pm, "Wayne Paul" > wrote:
>
>
>
> > "Darryl Ramm" > wrote in ...
> > > On Oct 28, 8:47 am, Andy > wrote:
>
> > > Just to give a flavor ADS-B data-out systems as mandated for 2020 in
> > > the USA for power aircraft (basically where a transponder is required
> > > today) will put out the following data
>
> > > Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
> > > Aircraft callsign/flight number (not required for VFR flight)
> > > Time of applicability
> > > GPS Lattitude
> > > GPS Longitude
> > > GPS altitude
> > > Airborne/on-surface status
> > > Northbound ground velocity component while airborne (from GPS)
> > > Eastbound ground velocity component while airborne (from GPS)
> > > Heading while on the surface
> > > Ground speed while on the surface
> > > Pressure altitude
> > > Vertical rate (may be pressure or GPS based)
> > > GPS uncertainty/integrity (which needs information form a fancy TSO-
> > > C145 class WAAS GPS)
> > > Ident (equivalent to transponder ident/SPI)
> > > Distress/Emergency status
> > > ADS-B data-in/display capability
> > > TCAS equipage/status
>
> > > This is a simplified list and there is various other status/validity
> > > data as well. There is also the concept in ADS-B messages of an
> > > estimated position, and even estimated velocity. But AFAIK this is not
> > > intended for fancy manoeuvrings predictions - it is more intended to
> > > allow different parts of the ADS-B infrastructure to project position
> > > or velocity updated to a single time of applicability. There is space
> > > for future expansion and as an example there is long-term work
> > > underway to look at an ADS-B based replacement for TCAS that could
> > > well utilize extra data transmission than that above, but think well
> > > post 2020 for this to actually happen. My brain hurts enough thinking
> > > about ADS-B as is.
>
> > > ---
>
> > > BTW my suspicion is given that the FAA currently requires a STC for
> > > any installation for ADS-B data out that it is currently not possible
> > > to install any ADS-B data-out system in the USA in any certified
> > > aircraft (including gliders) that only meets a subset of the 2020
> > > mandate requirements (ie. does not include all the stuff above). Which
> > > I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
> > > C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
> > > Experimental aircraft are another question since an STC cannot apply
> > > to them. This STC restriction hopefully is short-term as its is going
> > > to have a chilling effect on ADS-B data-out adoption in general
> > > aviation and gliders. Besides some more complex issues you can start
> > > to see even simple installation concerns that are probably causing
> > > this current STC requirement, such as squat switch/or other on-ground
> > > detection, needs to have a single squawk code and ident button across
> > > any installed transponder(s) and ADS-B data-out devices, ability to
> > > transmit a distress/emergency code, ability to turn off the ADS-B
> > > transmissions if requested, etc.
>
> > > Darryl
>
> > The following is not directed at any individual, it is simply an observation.
>
> > Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. *It is data output sentences are fully compliant with NMEA 0183 ver 2.0. *The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>
> > As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>
> > Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety..
>
> > Respectfully,
> > Wayne
>
> There have been several comment regarding the need for an STC to
> install an ADS-B system in a certified aircraft.
>
> This is not unlike the original situation with the installation of IFR
> certified GPS systems, in the early 1990s. *I was involved in several
> installations and most of the concerns were about the placement of
> antenna and the effect of spurious signals on navigation.
>
> Today if you get an IFR GPS installed in an aircraft the manufacturer
> has a detailed description of antenna placement, cable routing and
> possible interaction. *This data was collected during the earlier STC
> period and as experience with more installations was gained, the FAA
> changed the requirements from an STC to a 337, if installed in
> compliance with the manufacturer's instructions.
>
> I expect that the STC requirements for the ADS-B will follow the same
> path over time.
>
> Mike

Agreed completely. However, note that 1090 MHz
ADS-B (1090ES) uses the existing transponder antenna.
Much simpler than the early GPS situation.
However, UAT...

Hope that helps clarify the (not simple) situation,
Best Regards, Dave "YO electric"

Dave Nadler

October 28th 10, 11:40 PM

On Oct 28, 10:29*am, Mike Schumann >
wrote:
> I'm not an expert on either FLARM or ADS-B...
> --
> Mike Schumann

Finally, something we can all agree on ;-)
See ya, Dave "YO electric"

Mike Schumann

October 28th 10, 11:57 PM

On 10/28/2010 5:15 PM, Darryl Ramm wrote:
> On Oct 28, 1:54 pm, > wrote:
>> On Oct 28, 1:40 pm, "Wayne > wrote:
>>
>>
>>
>>> "Darryl > wrote in ...
>>>> On Oct 28, 8:47 am, > wrote:
>>
>>>> Just to give a flavor ADS-B data-out systems as mandated for 2020 in
>>>> the USA for power aircraft (basically where a transponder is required
>>>> today) will put out the following data
>>
>>>> Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
>>>> Aircraft callsign/flight number (not required for VFR flight)
>>>> Time of applicability
>>>> GPS Lattitude
>>>> GPS Longitude
>>>> GPS altitude
>>>> Airborne/on-surface status
>>>> Northbound ground velocity component while airborne (from GPS)
>>>> Eastbound ground velocity component while airborne (from GPS)
>>>> Heading while on the surface
>>>> Ground speed while on the surface
>>>> Pressure altitude
>>>> Vertical rate (may be pressure or GPS based)
>>>> GPS uncertainty/integrity (which needs information form a fancy TSO-
>>>> C145 class WAAS GPS)
>>>> Ident (equivalent to transponder ident/SPI)
>>>> Distress/Emergency status
>>>> ADS-B data-in/display capability
>>>> TCAS equipage/status
>>
>>>> This is a simplified list and there is various other status/validity
>>>> data as well. There is also the concept in ADS-B messages of an
>>>> estimated position, and even estimated velocity. But AFAIK this is not
>>>> intended for fancy manoeuvrings predictions - it is more intended to
>>>> allow different parts of the ADS-B infrastructure to project position
>>>> or velocity updated to a single time of applicability. There is space
>>>> for future expansion and as an example there is long-term work
>>>> underway to look at an ADS-B based replacement for TCAS that could
>>>> well utilize extra data transmission than that above, but think well
>>>> post 2020 for this to actually happen. My brain hurts enough thinking
>>>> about ADS-B as is.
>>
>>>> ---
>>
>>>> BTW my suspicion is given that the FAA currently requires a STC for
>>>> any installation for ADS-B data out that it is currently not possible
>>>> to install any ADS-B data-out system in the USA in any certified
>>>> aircraft (including gliders) that only meets a subset of the 2020
>>>> mandate requirements (ie. does not include all the stuff above). Which
>>>> I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
>>>> C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
>>>> Experimental aircraft are another question since an STC cannot apply
>>>> to them. This STC restriction hopefully is short-term as its is going
>>>> to have a chilling effect on ADS-B data-out adoption in general
>>>> aviation and gliders. Besides some more complex issues you can start
>>>> to see even simple installation concerns that are probably causing
>>>> this current STC requirement, such as squat switch/or other on-ground
>>>> detection, needs to have a single squawk code and ident button across
>>>> any installed transponder(s) and ADS-B data-out devices, ability to
>>>> transmit a distress/emergency code, ability to turn off the ADS-B
>>>> transmissions if requested, etc.
>>
>>>> Darryl
>>
>>> The following is not directed at any individual, it is simply an observation.
>>
>>> Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. It is data output sentences are fully compliant with NMEA 0183 ver 2.0. The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>>
>>> As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>>
>>> Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.
>>
>>> Respectfully,
>>> Wayne
>>
>> There have been several comment regarding the need for an STC to
>> install an ADS-B system in a certified aircraft.
>>
>> This is not unlike the original situation with the installation of IFR
>> certified GPS systems, in the early 1990s. I was involved in several
>> installations and most of the concerns were about the placement of
>> antenna and the effect of spurious signals on navigation.
>>
>> Today if you get an IFR GPS installed in an aircraft the manufacturer
>> has a detailed description of antenna placement, cable routing and
>> possible interaction. This data was collected during the earlier STC
>> period and as experience with more installations was gained, the FAA
>> changed the requirements from an STC to a 337, if installed in
>> compliance with the manufacturer's instructions.
>>
>> I expect that the STC requirements for the ADS-B will follow the same
>> path over time.
>>
>> Mike
>
> Absolutely right (and antenna issues are one of the concerns with this
> STC requirement as well). Its a matter of when the STC process
> migrates to a 337/Field approval. Given the complexity of ADS-B I
> wonder what the time frame will really be. And the FCC has stated that
> clearly but the STC requirement still seems to have come as a bit of a
> surprise to some developers--and maybe regulators where there are
> questions if the cost of this was included in disclosures. I see no
> way for now but for this to freeze a lot of adoption--but I suspect
> from the FAA viewpoint it is needed. I do worry that smaller
> manufacturers won't be able to develop many STCs and I am doubtful
> you'll see folks willing to develop STCs for gliders. My purpose of
> promoting the STC issue is just nobody seemed to be aware of it in
> the glider community yet there are (a few) owners starting to look at
> install of ADS-B data-out. Some of those owners have experimental
> gliders and are in a better position. Those with certified gliders
> need to have a discussion with vendors about STCs. In a practical
> sense as well most vendors are busy finishing off their "-B" rev data-
> out products (e.g. Garmin, Trig and others) and getting TSO approval
> on those. And I see that as a gate to STC approval, but clearly they
> could be overlapping TSO approval and STC development. And larger
> companies beside having lots of STC approval experience may also be
> able to leverage past ADS-B STC developed for trails, such as the
> GOMEX ADS-B trials.
>
>
> Darryl

I find it difficult to understand the "complexity" involved in ADS-B.
This is basically the same technology as FLARM (UAT) or Mode S
transponders (1090ES). The main difference between FLARM and UAT is the
frequency and power level of the transmitter. (Yes I know that UAT
doesn't include any of the collision detection logic of FLARM).

At some point, the FAA will figure this out or the whole ADS-B exercise
will come to a dead end.

--
Mike Schumann

Mike Schumann

October 29th 10, 12:03 AM

On 10/28/2010 3:36 PM, Eric Greenwell wrote:
> On 10/28/2010 11:32 AM, Mike Schumann wrote:
>>
>>
>> There's no question that FLARM or ADS-B based systems could have
>> easily prevented the Parowan mid-air. My question is how much you can
>> rely on this type of equipment to accurately warn you of collisions
>> when you are flying in gaggles.
>>
>> Obviously knowing the relative position of other gliders in the gaggle
>> is helpful. I would be very skeptical, however, of putting my faith in
>> FLARM or any other system to accurately warn me of a collision with
>> another glider that was in the same thermal, near my altitude, that
>> was in my blind spot.
> This situation is addressed at
>
> http://www.gliderpilot.org/FlarmFlightSituationsandPerformance
>
> where it states that the human eye is better than Flarm. I don't think
> anyone has claimed Flarm is better in every possible situation, and
> users and Flarm itself repeatedly state you must still look outside to
> have the best protection; however, I believe Flarm will indicate there
> is a glider behind you, something a pilot might not always be aware of,
> so it still has value in this situation.
>>
>> Transmitting the project path of the aircraft is really only
>> beneficial if the equipment on board the transmitting aircraft has
>> some added information that is not available to the receiver on the
>> transmitting aircraft's intent.
>>
>> With both FLARM and ADS-B systems, the initial visibility of the other
>> aircraft occurs way before there is any collision threat, so the
>> receiver should have no difficulty computing the project path of the
>> other aircraft. ADS-B actually transmits the category of aircraft
>> (i.e. glider, balloon, etc...) so the receiver can get a pretty good
>> hint on the type of maneuvers that can be expected.
> I can think of three situations where the time involved can be reduced:
>
> 1) two gliders approaching head on. At 100 knots each - a 200 knot
> closing speed - that's only 18 seconds or so to collision. How many
> seconds of warning do you lose while collecting enough points to make a
> good estimate of the projected paths - 5 seconds, 10 seconds? I don't
> know, but I'd prefer to know sooner than later.
>
> 2) Ridge or mountain flying, where the transmissions are blocked by the
> terrain. Once they round the corner of the ridge, there may not be
> enough time to calculate a projected path.
>
> 3) shortened range due to signal blockage by the wings or fuselage.
>
>

The proper logic on unexpectedly seeing a new target close by without
have a chance to compute trajectory is to use a worse case scenario.
Granted, having the trajectory as part of the transmission would be
helpful in this instance.

--
Mike Schumann

Mike Schumann

October 29th 10, 12:07 AM

On 10/28/2010 6:14 PM, Dave Nadler wrote:
> On Oct 28, 2:14 pm, Eric > wrote:
>>>> This projected path is a key element to the system working properly.
>>>> Without it, each FLARM unit would have to calculate the path of every
>>>> nearby glider; with it, each unit only has to calculate one path - it's
>>>> own. Potentially, it could be using a much higher position rate than
>>>> once a second to calculate it's projected path. In any case, the result
>>>> is much better than you might think for a system that transmits once a
>>>> second.
>>
>> ...
>> You may be underestimating the value of transmitting the projected path.
>> When another glider is first detected, your unit has only one position
>> report and can not determine the flight path from that single point, and
>> it will take several more precious seconds to determine the flight path
>> of the potential threat; however, because the projected path is
>> transmitted every second, your unit immediately knows it.
>>
>>> It would be interesting to get more detailed information on the exact
>>> algorithms that FLARM uses in it's collision threat analysis and
>>> compare this to the actual unit performance in situations where
>>> gliders are flying at close distances in formation or in gaggles.
>>> This could also help pilots understand the limitations of these
>>> systems so they don't develop a false sense of security in situations
>>> where these systems are not reliable.
>>
>> I'm sure the developers have tested their algorithms with thousands of
>> simulations using IGC files from gliders in many situations. The Parowan
>> accident simulation at
>>
>> http://www.gliderpilot.org/Flarm-ParowanMidairSimulation
>>
>> shows what can be done. It would be interesting, informative, and
>> entertaining if there was a website or application that would let us run
>> IGC files we select in a simulation like this. I'm curious about how
>> Flarm would react in a few situations I've encountered. Doing
>> simulations on a pilot's own files might be more persuasive of the value
>> of Flarm than even the most well-written explanations, and much more
>> easily understood than the algorithms themselves.
>
> If you watch the Parowan simulation carefully, you will see that
> the collision alarm sounds BEFORE the straight-line trajectories
> intersect. This is because one of the gliders is circling, and the
> projected trajectory (circling) shows a collision SECONDS
> before the straight-line trajectories intersect.
>
> These additional seconds can be a life-saver.
>
> Hope that helps clarify,
> Best Regards, Dave "YO electric"

I totally understand the advantage of using the expected trajectory in
computing the collision threat. The Parowan situation is an example of
a case where an ADS-B based system, with a sophisticated trajectory
algorithm in the receiving system would have been just as effective as
FLARM. Note: I am aware that such a system probably doesn't exist yet,
so let's not start a flame war over that issue.

--
Mike Schumann

[email protected]

October 29th 10, 01:46 AM

On Oct 28, 9:47*am, Andreas Maurer > wrote:
> On Tue, 26 Oct 2010 18:03:50 -0700 (PDT), John Cochrane
>
> > wrote:
> >"Idiot" is perhaps a bit strong, and I may have been hasty in applying
> >it to a fellow pilot. On the other hand, he did pass 10-20 feet over
> >the top of my glider in a large gaggle.
>
> One pilot who I know very well told me that during a WGC when he was
> competing for the first place (he was in the lead), one very-well
> known competitor flew maneuvres that this pilot could only classify as
> attempts to produce near-misses. Within half an hour they had two
> near-misses with less than fifteen feet, both provoked by the same
> pilot.
>
> Then the pilot in question lost his nerves and broke off the flight.
> The attacking pilot won the WGC.
>
> Andreas

Aha! Finally, somebody came out with the truth!

In my first post when I asked, "Are you thinking what I am
thinking?" THAT was what I was thinking!

Cookie

Eric Greenwell[_4_]

October 29th 10, 03:38 AM

On 10/28/2010 4:03 PM, Mike Schumann wrote:
> On 10/28/2010 3:36 PM, Eric Greenwell wrote:
>> I can think of three situations where the time involved can be reduced:
>>
>> 1) two gliders approaching head on. At 100 knots each - a 200 knot
>> closing speed - that's only 18 seconds or so to collision. How many
>> seconds of warning do you lose while collecting enough points to make a
>> good estimate of the projected paths - 5 seconds, 10 seconds? I don't
>> know, but I'd prefer to know sooner than later.
>>
>> 2) Ridge or mountain flying, where the transmissions are blocked by the
>> terrain. Once they round the corner of the ridge, there may not be
>> enough time to calculate a projected path.
>>
>> 3) shortened range due to signal blockage by the wings or fuselage.
> The proper logic on unexpectedly seeing a new target close by without
> have a chance to compute trajectory is to use a worse case scenario.
> Granted, having the trajectory as part of the transmission would be
> helpful in this instance.
And which way do you turn, when you don't know where the threat is going?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)

Darryl Ramm

October 29th 10, 04:21 AM

On Oct 28, 3:57*pm, Mike Schumann >
wrote:
> On 10/28/2010 5:15 PM, Darryl Ramm wrote:
>
>
>
>
>
>
>
> > On Oct 28, 1:54 pm, > *wrote:
> >> On Oct 28, 1:40 pm, "Wayne > *wrote:
>
> >>> "Darryl > *wrote in ...
> >>>> On Oct 28, 8:47 am, > *wrote:
>
> >>>> Just to give a flavor ADS-B data-out systems as mandated for 2020 in
> >>>> the USA for power aircraft (basically where a transponder is required
> >>>> today) will put out the following data
>
> >>>> Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
> >>>> Aircraft callsign/flight number (not required for VFR flight)
> >>>> Time of applicability
> >>>> GPS Lattitude
> >>>> GPS Longitude
> >>>> GPS altitude
> >>>> Airborne/on-surface status
> >>>> Northbound ground velocity component while airborne (from GPS)
> >>>> Eastbound ground velocity component while airborne (from GPS)
> >>>> Heading while on the surface
> >>>> Ground speed while on the surface
> >>>> Pressure altitude
> >>>> Vertical rate (may be pressure or GPS based)
> >>>> GPS uncertainty/integrity (which needs information form a fancy TSO-
> >>>> C145 class WAAS GPS)
> >>>> Ident (equivalent to transponder ident/SPI)
> >>>> Distress/Emergency status
> >>>> ADS-B data-in/display capability
> >>>> TCAS equipage/status
>
> >>>> This is a simplified list and there is various other status/validity
> >>>> data as well. There is also the concept in ADS-B messages of an
> >>>> estimated position, and even estimated velocity. But AFAIK this is not
> >>>> intended for fancy manoeuvrings predictions - it is more intended to
> >>>> allow different parts of the ADS-B infrastructure to project position
> >>>> or velocity updated to a single time of applicability. There is space
> >>>> for future expansion and as an example there is long-term work
> >>>> underway to look at an ADS-B based replacement for TCAS that could
> >>>> well utilize extra data transmission than that above, but think well
> >>>> post 2020 for this to actually happen. My brain hurts enough thinking
> >>>> about ADS-B as is.
>
> >>>> ---
>
> >>>> BTW my suspicion is given that the FAA currently requires a STC for
> >>>> any installation for ADS-B data out that it is currently not possible
> >>>> to install any ADS-B data-out system in the USA in any certified
> >>>> aircraft (including gliders) that only meets a subset of the 2020
> >>>> mandate requirements (ie. does not include all the stuff above). Which
> >>>> I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
> >>>> C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS..
> >>>> Experimental aircraft are another question since an STC cannot apply
> >>>> to them. This STC restriction hopefully is short-term as its is going
> >>>> to have a chilling effect on ADS-B data-out adoption in general
> >>>> aviation and gliders. Besides some more complex issues you can start
> >>>> to see even simple installation concerns that are probably causing
> >>>> this current STC requirement, such as squat switch/or other on-ground
> >>>> detection, needs to have a single squawk code and ident button across
> >>>> any installed transponder(s) and ADS-B data-out devices, ability to
> >>>> transmit a distress/emergency code, ability to turn off the ADS-B
> >>>> transmissions if requested, etc.
>
> >>>> Darryl
>
> >>> The following is not directed at any individual, it is simply an observation.
>
> >>> Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. *It is data output sentences are fully compliant with NMEA 0183 ver 2.0. *The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>
> >>> As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>
> >>> Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.
>
> >>> Respectfully,
> >>> Wayne
>
> >> There have been several comment regarding the need for an STC to
> >> install an ADS-B system in a certified aircraft.
>
> >> This is not unlike the original situation with the installation of IFR
> >> certified GPS systems, in the early 1990s. *I was involved in several
> >> installations and most of the concerns were about the placement of
> >> antenna and the effect of spurious signals on navigation.
>
> >> Today if you get an IFR GPS installed in an aircraft the manufacturer
> >> has a detailed description of antenna placement, cable routing and
> >> possible interaction. *This data was collected during the earlier STC
> >> period and as experience with more installations was gained, the FAA
> >> changed the requirements from an STC to a 337, if installed in
> >> compliance with the manufacturer's instructions.
>
> >> I expect that the STC requirements for the ADS-B will follow the same
> >> path over time.
>
> >> Mike
>
> > Absolutely right (and antenna issues are one of the concerns with this
> > STC requirement as well). Its a matter of when the STC process
> > migrates to a 337/Field approval. Given the complexity of ADS-B I
> > wonder what the time frame will really be. And the FCC has stated that
> > clearly but the STC requirement still seems to have come as a bit of a
> > surprise to some developers--and maybe regulators where there are
> > questions if the cost of this was included in disclosures. I see no
> > way for now but for this to freeze a lot of adoption--but I suspect
> > from the FAA viewpoint it is needed. I do worry that smaller
> > manufacturers won't be able to develop many STCs and I am doubtful
> > you'll see folks willing to develop STCs for gliders. My purpose of
> > promoting the STC issue is just nobody seemed to be *aware of it in
> > the glider community yet there are (a few) owners starting to look at
> > install of ADS-B data-out. Some of those owners have experimental
> > gliders and are in a better position. Those with certified gliders
> > need to have a discussion with vendors about STCs. In a practical
> > sense as well most vendors are busy finishing off their "-B" rev data-
> > out products (e.g. Garmin, Trig and others) and getting TSO approval
> > on those. And I see that as a gate to STC approval, but clearly they
> > could be overlapping TSO approval and STC development. And larger
> > companies beside having lots of STC approval experience may also be
> > able to leverage past ADS-B STC developed for trails, such as the
> > GOMEX ADS-B trials.
>
> > Darryl
>
> I find it difficult to understand the "complexity" involved in ADS-B.
> This is basically the same technology as FLARM (UAT) or Mode S
> transponders (1090ES). *The main difference between FLARM and UAT is the
> frequency and power level of the transmitter. *(Yes I know that UAT
> doesn't include any of the collision detection logic of FLARM).
>
> At some point, the FAA will figure this out or the whole ADS-B exercise
> will come to a dead end.
>
> --
> Mike Schumann

ADS-B and its implementation and role in NextGen and all the different
players looking at this beast from all different angles and trying to
solve all sorts of different problems makes this is one of the most
complex undertakings ever in aviation.... and that includes everything
from the details of the data transmitted on up (e.g. the GPS chip in a
Flarm likely costs a few tens of dollars at most, a GPS box or module
for an ADS-B data-out TSO'ed product currently costs thousands of
dollars). All that extra stuff and bureaucracy that make it cost that
much really has no practical benefit for glider-glider collision
avoidance but has benefits to others.

Lets see, ADS-B data-out, ADS-B data-in, 1090ES, UAT, ADS-R, TIS-B,
FIS-B, surface surveillance, terminal surveillance, en-route
surveillance, essential services, critical services, TSO-C166b/
DO-260B, TSO-C154c/DO-282B, TSO-C145a/TSO-C146a WAAS GPS, SIL, NIC,
STCs, ... if this does not make your head ache you may not be thinking
about it hard enough. Most people just don't need to worry since this
is all years away from being interesting for them. Years away when FAA
ground services, ADS-B products, product cost, fleet adoption and
market awareness all start to line up.

And this applies to the ADS-B receiver part PowerFLARM as well -
especially its dependence on having ADS-B out for ADS-R and TIS-B to
work. There is a lot more the FAA and its providers have to do and
there is a lot more we all have to do to understand all this
technology and how best to use it moving forward - given that by 2020
a significant part of the entire USA aircraft fleet will be ADS-B data-
out equipped. But again I'm not trying to hawk ADS-B as being at all
ready for our market now, but I've very happy to see products like
PowerFLARM providing a path to include that in future.

Darryl

Andy[_10_]

October 29th 10, 05:19 AM

On Oct 28, 4:07*pm, Mike Schumann >
wrote:
> On 10/28/2010 6:14 PM, Dave Nadler wrote:
>
>
>
>
>
> > On Oct 28, 2:14 pm, Eric > *wrote:
> >>>> This projected path is a key element to the system working properly.
> >>>> Without it, each FLARM unit would have to calculate the path of every
> >>>> nearby glider; with it, each unit only has to calculate one path - it's
> >>>> own. Potentially, it could be using a much higher position rate than
> >>>> once a second to calculate it's projected path. In any case, the result
> >>>> is much better than you might think for a system that transmits once a
> >>>> second.
>
> >> ...
> >> You may be underestimating the value of transmitting the projected path.
> >> When another glider is first detected, your unit has only one position
> >> report and can not determine the flight path from that single point, and
> >> it will take several more precious seconds to determine the flight path
> >> of the potential threat; however, because the projected path is
> >> transmitted every second, your unit immediately knows it.
>
> >>> It would be interesting to get more detailed information on the exact
> >>> algorithms that FLARM uses in it's collision threat analysis and
> >>> compare this to the actual unit performance in situations where
> >>> gliders are flying at close distances in formation or in gaggles.
> >>> This could also help pilots understand the limitations of these
> >>> systems so they don't develop a false sense of security in situations
> >>> where these systems are not reliable.
>
> >> I'm sure the developers have tested their algorithms with thousands of
> >> simulations using IGC files from gliders in many situations. The Parowan
> >> accident simulation at
>
> >>http://www.gliderpilot.org/Flarm-ParowanMidairSimulation
>
> >> shows what can be done. It would be interesting, informative, and
> >> entertaining if there was a website or application that would let us run
> >> IGC files we select in a simulation like this. I'm curious about how
> >> Flarm would react in a few situations I've encountered. Doing
> >> simulations on a pilot's own files might be more persuasive of the value
> >> of Flarm than even the most well-written explanations, and much more
> >> easily understood than the algorithms themselves.
>
> > If you watch the Parowan simulation carefully, you will see that
> > the collision alarm sounds BEFORE the straight-line trajectories
> > intersect. This is because one of the gliders is circling, and the
> > projected trajectory (circling) shows a collision SECONDS
> > before the straight-line trajectories intersect.
>
> > These additional seconds can be a life-saver.
>
> > Hope that helps clarify,
> > Best Regards, Dave "YO electric"
>
> I totally understand the advantage of using the expected trajectory in
> computing the collision threat. *The Parowan situation is an example of
> a case where an ADS-B based system, with a sophisticated trajectory
> algorithm in the receiving system would have been just as effective as
> FLARM. *Note: *I am aware that such a system probably doesn't exist yet,
> so let's not start a flame war over that issue.
>
> --
> Mike Schumann

Actually I don't think that's necessarily true Mike. There potentially
is a difference in some critical situations between each aircraft
estimating the other aircraft's projected path and having each
aircraft send the other it's on-board estimated path. In the first
case there is no way to close the loop on path estimation differences
between the two aircraft - that is, my estimate of where you are going
can differ from your estimate of where you are going, and vice versa.
It may in fact be better to exchange projected paths to take the
biases out of the system. There also may be lag effects on projected
flight path changes due to maneuvering. It's quite possible that my
onboard system will be faster to include maneuvering effects on the
projected path than trying to piece it together from simple GPS
location and velocity transmissions.

The thing I found particularly impressive about the Parowan
demonstration was how both Flarm units gave nearly identical,
complementary warnings. I'm not sure that would have been the case
using ADS-B on-board estimations of the other glider's path. It's even
worse if the two ADS-B systems use different algorithms. Flarm and
PowerFlarm solve this problem.

9B

Andy[_10_]

October 29th 10, 05:51 AM

On Oct 28, 9:19*pm, Andy > wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B

Mike Schumann

October 29th 10, 07:02 AM

On 10/28/2010 10:38 PM, Eric Greenwell wrote:
> On 10/28/2010 4:03 PM, Mike Schumann wrote:
>> On 10/28/2010 3:36 PM, Eric Greenwell wrote:
>>> I can think of three situations where the time involved can be reduced:
>>>
>>> 1) two gliders approaching head on. At 100 knots each - a 200 knot
>>> closing speed - that's only 18 seconds or so to collision. How many
>>> seconds of warning do you lose while collecting enough points to make a
>>> good estimate of the projected paths - 5 seconds, 10 seconds? I don't
>>> know, but I'd prefer to know sooner than later.
>>>
>>> 2) Ridge or mountain flying, where the transmissions are blocked by the
>>> terrain. Once they round the corner of the ridge, there may not be
>>> enough time to calculate a projected path.
>>>
>>> 3) shortened range due to signal blockage by the wings or fuselage.
>> The proper logic on unexpectedly seeing a new target close by without
>> have a chance to compute trajectory is to use a worse case scenario.
>> Granted, having the trajectory as part of the transmission would be
>> helpful in this instance.
> And which way do you turn, when you don't know where the threat is going?
>

It appears that ADS-B does transmit the location as well as the
instantaneous velocity vector each second, so if you have a graphical
display, you will be able to see the orientation and physical location
of the aircraft immediately. It doesn't currently transmit any turn
rate info. I don't know if it gives you any data on rate of climb /
descent.

A basic FLARM unit, without a graphical display, won't give you any
hints of which direction the target is moving in. It will only give you
a rough idea of where the threat target is, so you have to use your eyes
and judgment to take evasive action.

I suspect that a graphical display is primarily useful to identify the
location and course info for aircraft in your area before you get into
an alarm condition. Once the alarm goes off, you should probably be
looking outside. (Not having flown with these types of units, others
probably have better insights into this).

--
Mike Schumann

Mike Schumann

October 29th 10, 07:20 AM

On 10/29/2010 12:51 AM, Andy wrote:
> On Oct 28, 9:19 pm, > wrote:
>
> Also, to clarify, ADS-B does no path estimation of its own. That
> function either would have to be added into an ADS-B unit by the OEM,
> similar to the way Flarm does today - unlikely to be done in a glider-
> specific way IMO - OR, it would have to be done by a separate external
> device, perhaps a navigation computer/software like Oudie, WinPilot,
> SN-10. For it to be effective manufacturers would all have to agree to
> use the same algorithm, which also seems unlikely, unless they all
> adopt the Flarm algorithm. That seems somewhat unlikely too, since I
> don't think Flarm would want to start splintering how their algorithms
> get used by splitting out the Flarm link technology from the collision
> algorithm (which would have to be modified to accommodate the
> differences in how path estimations get generated - with unpredictable
> results). PLUS the external device OEM's would have to adapt to using
> ADS-B inputs - another standards issue.
>
> No matter how hard I try, it seems highly improbable that you will be
> able to stitch together a satisfactory collision avoidance system for
> gliders using ADS-B technology developed for general aviation. You'd
> have to be satisfied with the simple functionality offered by ADS-B -
> which would be fine if you generally come into conflict with GA and
> airliners more often than other gliders, but there are a bunch of us
> for whom the opposite is true. Then the problem becomes some gliders
> using Flarm and others using ADS-B, you lose some of the Flarm
> benefits of path estimation for the non-Flarm gliders.
>
> 9B
>
> 9B
>

You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. It was two gliders who apparently did not have a
proper appreciation that they were near each other. A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann

Andy[_10_]

October 29th 10, 10:11 AM

On Oct 28, 11:20*pm, Mike Schumann >
wrote:
> On 10/29/2010 12:51 AM, Andy wrote:
>
>
>
>
>
> > On Oct 28, 9:19 pm, > *wrote:
>
> > Also, to clarify, ADS-B does no path estimation of its own. That
> > function either would have to be added into an ADS-B unit by the OEM,
> > similar to the way Flarm does today - unlikely to be done in a glider-
> > specific way IMO - OR, it would have to be done by a separate external
> > device, perhaps a navigation computer/software like Oudie, WinPilot,
> > SN-10. For it to be effective manufacturers would all have to agree to
> > use the same algorithm, which also seems unlikely, unless they all
> > adopt the Flarm algorithm. That seems somewhat unlikely too, since I
> > don't think Flarm would want to start splintering how their algorithms
> > get used by splitting out the Flarm link technology from the collision
> > algorithm (which would have to be modified to accommodate the
> > differences in how path estimations get generated - with unpredictable
> > results). PLUS the external device OEM's would have to adapt to using
> > ADS-B inputs - another standards issue.
>
> > No matter how hard I try, it seems highly improbable that you will be
> > able to stitch together a satisfactory collision avoidance system for
> > gliders using ADS-B technology developed for general aviation. You'd
> > have to be satisfied with the simple functionality offered by ADS-B -
> > which would be fine if you *generally come into conflict with GA and
> > airliners more often than other gliders, but there are a bunch of us
> > for whom the opposite is true. Then the problem becomes some gliders
> > using Flarm and others using ADS-B, you lose some of the Flarm
> > benefits of path estimation for the non-Flarm gliders.
>
> > 9B
>
> > 9B
>
> You are probably correct that no one is going to beat FLARM in an
> optimized collision avoidance solution for high density glider
> environments. *That's obviously their focus and they are good at it.
>
> However, most recreational, non-contest pilots, primarily need a system
> that will reliably alert them to other aircraft in their general
> vicinity. *If I enter a thermal and know that there are 3 other aircraft
> in the area, and I only see two, I'm going to abort and go elsewhere. *A
> contest pilot obviously wants more data.
>
> What is interesting about the Parowan situation is that this was not a
> gaggle of gliders. *It was two gliders who apparently did not have a
> proper appreciation that they were near each other. *A simple graphical
> display that showed their relative positions, with a very simple
> collision avoidance algorithm, or some form of auditory announcement
> could have prevented this accident. *That's not to say that the FLARM
> simulation was not impressive.
>
> --
> Mike Schumann

I played back the igc files from all the gliders flying that day and
can say that your speculation is not really supported by the facts.
Actually there were a number of gliders in that thermal - as it turns
out I passed right by it about a minute after the collision. There was
also a lot of non-thermalling traffic going in both directions at the
time, mostly within a pretty narrow altitude band within a thousand
feet or two of cloud base under a long cloud street.

An issue in these kinds of situations is that you can fixate on a
couple of gliders a bit higher in the thermal and miss the one
entering on a collision course with you at nearly the same time. A
cruder collision system has the potential to false alarm on too many
non-threats and on multiple gliders in the vicinity, making it hard
for the pilot to sort out which one is the real threat. Or it can
falsely identify a non-threat and mask the one that is really the
problem.

At this point I'm not at all sure why you'd pick straight ADS-B
(especially UAT) over something like PowerFlarm. The arguments keep
changing and hard as I try I can't find one that holds water when I
really run through all the issues. I think ADS-B in the long run is a
decent upgrade over PCAS, but PowerFlarm is more cost efficient and
more effective as a collision warning system, plus it has ADS-B in and
PCAS build in.

Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
well prior to ADS-B getting out from under the STC requirement.

9B

Mike Schumann

October 29th 10, 04:16 PM

On 10/28/2010 10:21 PM, Darryl Ramm wrote:
> On Oct 28, 3:57 pm, Mike >
> wrote:
>> On 10/28/2010 5:15 PM, Darryl Ramm wrote:
>>
>>
>>
>>
>>
>>
>>
>>> On Oct 28, 1:54 pm, > wrote:
>>>> On Oct 28, 1:40 pm, "Wayne > wrote:
>>
>>>>> "Darryl > wrote in ...
>>>>>> On Oct 28, 8:47 am, > wrote:
>>
>>>>>> Just to give a flavor ADS-B data-out systems as mandated for 2020 in
>>>>>> the USA for power aircraft (basically where a transponder is required
>>>>>> today) will put out the following data
>>
>>>>>> Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
>>>>>> Aircraft callsign/flight number (not required for VFR flight)
>>>>>> Time of applicability
>>>>>> GPS Lattitude
>>>>>> GPS Longitude
>>>>>> GPS altitude
>>>>>> Airborne/on-surface status
>>>>>> Northbound ground velocity component while airborne (from GPS)
>>>>>> Eastbound ground velocity component while airborne (from GPS)
>>>>>> Heading while on the surface
>>>>>> Ground speed while on the surface
>>>>>> Pressure altitude
>>>>>> Vertical rate (may be pressure or GPS based)
>>>>>> GPS uncertainty/integrity (which needs information form a fancy TSO-
>>>>>> C145 class WAAS GPS)
>>>>>> Ident (equivalent to transponder ident/SPI)
>>>>>> Distress/Emergency status
>>>>>> ADS-B data-in/display capability
>>>>>> TCAS equipage/status
>>
>>>>>> This is a simplified list and there is various other status/validity
>>>>>> data as well. There is also the concept in ADS-B messages of an
>>>>>> estimated position, and even estimated velocity. But AFAIK this is not
>>>>>> intended for fancy manoeuvrings predictions - it is more intended to
>>>>>> allow different parts of the ADS-B infrastructure to project position
>>>>>> or velocity updated to a single time of applicability. There is space
>>>>>> for future expansion and as an example there is long-term work
>>>>>> underway to look at an ADS-B based replacement for TCAS that could
>>>>>> well utilize extra data transmission than that above, but think well
>>>>>> post 2020 for this to actually happen. My brain hurts enough thinking
>>>>>> about ADS-B as is.
>>
>>>>>> ---
>>
>>>>>> BTW my suspicion is given that the FAA currently requires a STC for
>>>>>> any installation for ADS-B data out that it is currently not possible
>>>>>> to install any ADS-B data-out system in the USA in any certified
>>>>>> aircraft (including gliders) that only meets a subset of the 2020
>>>>>> mandate requirements (ie. does not include all the stuff above). Which
>>>>>> I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
>>>>>> C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
>>>>>> Experimental aircraft are another question since an STC cannot apply
>>>>>> to them. This STC restriction hopefully is short-term as its is going
>>>>>> to have a chilling effect on ADS-B data-out adoption in general
>>>>>> aviation and gliders. Besides some more complex issues you can start
>>>>>> to see even simple installation concerns that are probably causing
>>>>>> this current STC requirement, such as squat switch/or other on-ground
>>>>>> detection, needs to have a single squawk code and ident button across
>>>>>> any installed transponder(s) and ADS-B data-out devices, ability to
>>>>>> transmit a distress/emergency code, ability to turn off the ADS-B
>>>>>> transmissions if requested, etc.
>>
>>>>>> Darryl
>>
>>>>> The following is not directed at any individual, it is simply an observation.
>>
>>>>> Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. It is data output sentences are fully compliant with NMEA 0183 ver 2.0. The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf
>>
>>>>> As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.
>>
>>>>> Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.
>>
>>>>> Respectfully,
>>>>> Wayne
>>
>>>> There have been several comment regarding the need for an STC to
>>>> install an ADS-B system in a certified aircraft.
>>
>>>> This is not unlike the original situation with the installation of IFR
>>>> certified GPS systems, in the early 1990s. I was involved in several
>>>> installations and most of the concerns were about the placement of
>>>> antenna and the effect of spurious signals on navigation.
>>
>>>> Today if you get an IFR GPS installed in an aircraft the manufacturer
>>>> has a detailed description of antenna placement, cable routing and
>>>> possible interaction. This data was collected during the earlier STC
>>>> period and as experience with more installations was gained, the FAA
>>>> changed the requirements from an STC to a 337, if installed in
>>>> compliance with the manufacturer's instructions.
>>
>>>> I expect that the STC requirements for the ADS-B will follow the same
>>>> path over time.
>>
>>>> Mike
>>
>>> Absolutely right (and antenna issues are one of the concerns with this
>>> STC requirement as well). Its a matter of when the STC process
>>> migrates to a 337/Field approval. Given the complexity of ADS-B I
>>> wonder what the time frame will really be. And the FCC has stated that
>>> clearly but the STC requirement still seems to have come as a bit of a
>>> surprise to some developers--and maybe regulators where there are
>>> questions if the cost of this was included in disclosures. I see no
>>> way for now but for this to freeze a lot of adoption--but I suspect
>>> from the FAA viewpoint it is needed. I do worry that smaller
>>> manufacturers won't be able to develop many STCs and I am doubtful
>>> you'll see folks willing to develop STCs for gliders. My purpose of
>>> promoting the STC issue is just nobody seemed to be aware of it in
>>> the glider community yet there are (a few) owners starting to look at
>>> install of ADS-B data-out. Some of those owners have experimental
>>> gliders and are in a better position. Those with certified gliders
>>> need to have a discussion with vendors about STCs. In a practical
>>> sense as well most vendors are busy finishing off their "-B" rev data-
>>> out products (e.g. Garmin, Trig and others) and getting TSO approval
>>> on those. And I see that as a gate to STC approval, but clearly they
>>> could be overlapping TSO approval and STC development. And larger
>>> companies beside having lots of STC approval experience may also be
>>> able to leverage past ADS-B STC developed for trails, such as the
>>> GOMEX ADS-B trials.
>>
>>> Darryl
>>
>> I find it difficult to understand the "complexity" involved in ADS-B.
>> This is basically the same technology as FLARM (UAT) or Mode S
>> transponders (1090ES). The main difference between FLARM and UAT is the
>> frequency and power level of the transmitter. (Yes I know that UAT
>> doesn't include any of the collision detection logic of FLARM).
>>
>> At some point, the FAA will figure this out or the whole ADS-B exercise
>> will come to a dead end.
>>
>> --
>> Mike Schumann
>
> ADS-B and its implementation and role in NextGen and all the different
> players looking at this beast from all different angles and trying to
> solve all sorts of different problems makes this is one of the most
> complex undertakings ever in aviation.... and that includes everything
> from the details of the data transmitted on up (e.g. the GPS chip in a
> Flarm likely costs a few tens of dollars at most, a GPS box or module
> for an ADS-B data-out TSO'ed product currently costs thousands of
> dollars). All that extra stuff and bureaucracy that make it cost that
> much really has no practical benefit for glider-glider collision
> avoidance but has benefits to others.
>
> Lets see, ADS-B data-out, ADS-B data-in, 1090ES, UAT, ADS-R, TIS-B,
> FIS-B, surface surveillance, terminal surveillance, en-route
> surveillance, essential services, critical services, TSO-C166b/
> DO-260B, TSO-C154c/DO-282B, TSO-C145a/TSO-C146a WAAS GPS, SIL, NIC,
> STCs, ... if this does not make your head ache you may not be thinking
> about it hard enough. Most people just don't need to worry since this
> is all years away from being interesting for them. Years away when FAA
> ground services, ADS-B products, product cost, fleet adoption and
> market awareness all start to line up.
>
> And this applies to the ADS-B receiver part PowerFLARM as well -
> especially its dependence on having ADS-B out for ADS-R and TIS-B to
> work. There is a lot more the FAA and its providers have to do and
> there is a lot more we all have to do to understand all this
> technology and how best to use it moving forward - given that by 2020
> a significant part of the entire USA aircraft fleet will be ADS-B data-
> out equipped. But again I'm not trying to hawk ADS-B as being at all
> ready for our market now, but I've very happy to see products like
> PowerFLARM providing a path to include that in future.
>
> Darryl

You are confusing ADS-B and everything else under the "Nextgen" umbrella.

ADS-B is fundamentally a very simple concept. You have a GPS in your
airplane, and once a second you transmit your position and velocity
vector data. On the receive side, you listen and receive everyone
else's position. Additional data may also be available if you are
interested (weather, Notams, etc.).

ADS-B is basically the same as FLARM, except that FLARM also includes
collision avoidance features that need to be implemented externally to
the ADS-B transceiver, if the user desires this capability. The only
fundamental differences between ADS-B and FLARM is the frequency used to
communicate between aircraft, the power level of the transmitters and
the protocol used. There is no technical reason that the US version of
FLARM data link could not have been implemented to be ADS-B compatible.
Granted, the FLARM guys would have had to invest in extra engineering
to change their protocols, and then would have had to deal with the FAA
BS involved with ADS-B, so it is totally understandable, from a business
perspective, why they did not go down this path.

The problem with ADS-B is all the regulatory crap and "integrity" BS
that the FAA dumped on the avionics manufacturers that has made it
impossible to develop hardware at an affordable price point. The
"complexity" is not in the fundamental technology, but in working thru
the FAA process to get this equipment approved.

It is a huge failure of the FAA, AOPA, the SSA, and the rest of the US
aviation community that this program has turned into such a fiasco. If
the fundamental focus had been on affordability, there is no reason that
we couldn't now have commercial ADS-B equipment at the same price points
as FLARM units.

--
Mike Schumann

Mike Schumann

October 29th 10, 04:32 PM

On 10/29/2010 4:11 AM, Andy wrote:
> On Oct 28, 11:20 pm, Mike >
> wrote:
>> On 10/29/2010 12:51 AM, Andy wrote:
>>
>>
>>
>>
>>
>>> On Oct 28, 9:19 pm, > wrote:
>>
>>> Also, to clarify, ADS-B does no path estimation of its own. That
>>> function either would have to be added into an ADS-B unit by the OEM,
>>> similar to the way Flarm does today - unlikely to be done in a glider-
>>> specific way IMO - OR, it would have to be done by a separate external
>>> device, perhaps a navigation computer/software like Oudie, WinPilot,
>>> SN-10. For it to be effective manufacturers would all have to agree to
>>> use the same algorithm, which also seems unlikely, unless they all
>>> adopt the Flarm algorithm. That seems somewhat unlikely too, since I
>>> don't think Flarm would want to start splintering how their algorithms
>>> get used by splitting out the Flarm link technology from the collision
>>> algorithm (which would have to be modified to accommodate the
>>> differences in how path estimations get generated - with unpredictable
>>> results). PLUS the external device OEM's would have to adapt to using
>>> ADS-B inputs - another standards issue.
>>
>>> No matter how hard I try, it seems highly improbable that you will be
>>> able to stitch together a satisfactory collision avoidance system for
>>> gliders using ADS-B technology developed for general aviation. You'd
>>> have to be satisfied with the simple functionality offered by ADS-B -
>>> which would be fine if you generally come into conflict with GA and
>>> airliners more often than other gliders, but there are a bunch of us
>>> for whom the opposite is true. Then the problem becomes some gliders
>>> using Flarm and others using ADS-B, you lose some of the Flarm
>>> benefits of path estimation for the non-Flarm gliders.
>>
>>> 9B
>>
>>> 9B
>>
>> You are probably correct that no one is going to beat FLARM in an
>> optimized collision avoidance solution for high density glider
>> environments. That's obviously their focus and they are good at it.
>>
>> However, most recreational, non-contest pilots, primarily need a system
>> that will reliably alert them to other aircraft in their general
>> vicinity. If I enter a thermal and know that there are 3 other aircraft
>> in the area, and I only see two, I'm going to abort and go elsewhere. A
>> contest pilot obviously wants more data.
>>
>> What is interesting about the Parowan situation is that this was not a
>> gaggle of gliders. It was two gliders who apparently did not have a
>> proper appreciation that they were near each other. A simple graphical
>> display that showed their relative positions, with a very simple
>> collision avoidance algorithm, or some form of auditory announcement
>> could have prevented this accident. That's not to say that the FLARM
>> simulation was not impressive.
>>
>> --
>> Mike Schumann
>
> I played back the igc files from all the gliders flying that day and
> can say that your speculation is not really supported by the facts.
> Actually there were a number of gliders in that thermal - as it turns
> out I passed right by it about a minute after the collision. There was
> also a lot of non-thermalling traffic going in both directions at the
> time, mostly within a pretty narrow altitude band within a thousand
> feet or two of cloud base under a long cloud street.
>
> An issue in these kinds of situations is that you can fixate on a
> couple of gliders a bit higher in the thermal and miss the one
> entering on a collision course with you at nearly the same time. A
> cruder collision system has the potential to false alarm on too many
> non-threats and on multiple gliders in the vicinity, making it hard
> for the pilot to sort out which one is the real threat. Or it can
> falsely identify a non-threat and mask the one that is really the
> problem.
>
> At this point I'm not at all sure why you'd pick straight ADS-B
> (especially UAT) over something like PowerFlarm. The arguments keep
> changing and hard as I try I can't find one that holds water when I
> really run through all the issues. I think ADS-B in the long run is a
> decent upgrade over PCAS, but PowerFlarm is more cost efficient and
> more effective as a collision warning system, plus it has ADS-B in and
> PCAS build in.
>
> Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
> well prior to ADS-B getting out from under the STC requirement.
>
> 9B

Contrary to what everyone seems to think, I am not fundamentally opposed
to PowerFLARM. I understand the sophistication of its collision
avoidance logic, and it is very impressive and useful. I totally get
the necessity for reducing false alarms, so that the alarms that are
issued are meaningful.

My disappointment with PowerFLARM is the lack of a clear plan to take
advantage of the extensive ADS-B ground station infrastructure that will
cover much of the US in the next year or so, to provide the same level
of collision avoidance to transponder equipped GA and commercial traffic
that is available between PowerFLARM equipped gliders.

Granted, the PCAS capability built into PowerFLARM gives you some level
of protection, but you have no information on relative direction of the
threat, and a very crude estimate of its range. I find it very
difficult to understand how PowerFLARM will be able to suppress PCAS
initiated alarms from Mode C transponder equipped gliders in a gaggle,
while simultaneously still generating PCAS alarms from other GA aircraft
that also in the area.

The built-in 1090ES ADS-B In capability is great, but that doesn't
provide any ground station originated data unless you are transmitting
ADS-B out. The new Trig Mode S transponders provide this capability,
but require a GPS source. Is PowerFLARM going to provide this, or what
is the plan for glider pilots to end up with a complete ADS-B compatible
solution?

--
Mike Schumann

mattm[_2_]

October 29th 10, 04:52 PM

On Oct 29, 11:32*am, Mike Schumann >
wrote:
> On 10/29/2010 4:11 AM, Andy wrote:
>
>
>
> > On Oct 28, 11:20 pm, Mike >
> > wrote:
> >> On 10/29/2010 12:51 AM, Andy wrote:
>
> >>> On Oct 28, 9:19 pm, > * *wrote:
>
> >>> Also, to clarify, ADS-B does no path estimation of its own. That
> >>> function either would have to be added into an ADS-B unit by the OEM,
> >>> similar to the way Flarm does today - unlikely to be done in a glider-
> >>> specific way IMO - OR, it would have to be done by a separate external
> >>> device, perhaps a navigation computer/software like Oudie, WinPilot,
> >>> SN-10. For it to be effective manufacturers would all have to agree to
> >>> use the same algorithm, which also seems unlikely, unless they all
> >>> adopt the Flarm algorithm. That seems somewhat unlikely too, since I
> >>> don't think Flarm would want to start splintering how their algorithms
> >>> get used by splitting out the Flarm link technology from the collision
> >>> algorithm (which would have to be modified to accommodate the
> >>> differences in how path estimations get generated - with unpredictable
> >>> results). PLUS the external device OEM's would have to adapt to using
> >>> ADS-B inputs - another standards issue.
>
> >>> No matter how hard I try, it seems highly improbable that you will be
> >>> able to stitch together a satisfactory collision avoidance system for
> >>> gliders using ADS-B technology developed for general aviation. You'd
> >>> have to be satisfied with the simple functionality offered by ADS-B -
> >>> which would be fine if you *generally come into conflict with GA and
> >>> airliners more often than other gliders, but there are a bunch of us
> >>> for whom the opposite is true. Then the problem becomes some gliders
> >>> using Flarm and others using ADS-B, you lose some of the Flarm
> >>> benefits of path estimation for the non-Flarm gliders.
>
> >>> 9B
>
> >>> 9B
>
> >> You are probably correct that no one is going to beat FLARM in an
> >> optimized collision avoidance solution for high density glider
> >> environments. *That's obviously their focus and they are good at it.
>
> >> However, most recreational, non-contest pilots, primarily need a system
> >> that will reliably alert them to other aircraft in their general
> >> vicinity. *If I enter a thermal and know that there are 3 other aircraft
> >> in the area, and I only see two, I'm going to abort and go elsewhere. *A
> >> contest pilot obviously wants more data.
>
> >> What is interesting about the Parowan situation is that this was not a
> >> gaggle of gliders. *It was two gliders who apparently did not have a
> >> proper appreciation that they were near each other. *A simple graphical
> >> display that showed their relative positions, with a very simple
> >> collision avoidance algorithm, or some form of auditory announcement
> >> could have prevented this accident. *That's not to say that the FLARM
> >> simulation was not impressive.
>
> >> --
> >> Mike Schumann
>
> > I played back the igc files from all the gliders flying that day and
> > can say that your speculation is not really supported by the facts.
> > Actually there were a number of gliders in that thermal - as it turns
> > out I passed right by it about a minute after the collision. There was
> > also a lot of non-thermalling traffic going in both directions at the
> > time, mostly within a pretty narrow altitude band within a thousand
> > feet or two of cloud base under a long cloud street.
>
> > An issue in these kinds of situations is that you can fixate on a
> > couple of gliders a bit higher in the thermal and miss the one
> > entering on a collision course with you at nearly the same time. *A
> > cruder collision system has the potential to false alarm on too many
> > non-threats and on multiple gliders in the vicinity, making it hard
> > for the pilot to sort out which one is the real threat. Or it can
> > falsely identify a non-threat and mask the one that is really the
> > problem.
>
> > At this point I'm not at all sure why you'd pick straight ADS-B
> > (especially UAT) over something like PowerFlarm. The arguments keep
> > changing and hard as I try I can't find one that holds water when I
> > really run through all the issues. I think ADS-B in the long run is a
> > decent upgrade over PCAS, but PowerFlarm is more cost efficient and
> > more effective as a collision warning system, plus it has ADS-B in and
> > PCAS build in.
>
> > Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
> > well prior to ADS-B getting out from under the STC requirement.
>
> > 9B
>
> Contrary to what everyone seems to think, I am not fundamentally opposed
> to PowerFLARM. *I understand the sophistication of its collision
> avoidance logic, and it is very impressive and useful. *I totally get
> the necessity for reducing false alarms, so that the alarms that are
> issued are meaningful.
>
> My disappointment with PowerFLARM is the lack of a clear plan to take
> advantage of the extensive ADS-B ground station infrastructure that will
> cover much of the US in the next year or so, to provide the same level
> of collision avoidance to transponder equipped GA and commercial traffic
> that is available between PowerFLARM equipped gliders.
>
> Granted, the PCAS capability built into PowerFLARM gives you some level
> of protection, but you have no information on relative direction of the
> threat, and a very crude estimate of its range. *I find it very
> difficult to understand how PowerFLARM will be able to suppress PCAS
> initiated alarms from Mode C transponder equipped gliders in a gaggle,
> while simultaneously still generating PCAS alarms from other GA aircraft
> that also in the area.
>
> The built-in 1090ES ADS-B In capability is great, but that doesn't
> provide any ground station originated data unless you are transmitting
> ADS-B out. *The new Trig Mode S transponders provide this capability,
> but require a GPS source. *Is PowerFLARM going to provide this, or what
> is the plan for glider pilots to end up with a complete ADS-B compatible
> solution?
>
> --
> Mike Schumann

Somewhere earlier in this thread someone noted that they were planning
on doing that soon. I plan on doing it myself, except that the $4K
pricetag
means it will take a while to save up for it. Also, the TSO fiasco
throws
a big question mark over the ADS-B out part of the equation. My plane
(ASW-19) is type certified in the US, so the TSO requirement applies
to me.

-- Matt

[email protected]

October 29th 10, 05:00 PM

On 10/29/2010 11:16 AM, Mike Schumann wrote:
> If the fundamental focus had been on affordability, there is no reason
> that we couldn't now have commercial ADS-B equipment at the same price
> points as FLARM units.

NavWorx announced on Wednesday Oct. 27 that they are currently shipping
the ADS600B transceivers.
They offer their informal solution to the FAA's STC and/or TSO mandates
> can be installed on both experimental and certified aircraft when it meets “portable installation guidelines.”<

kirk.stant

October 29th 10, 05:37 PM

Mike, I think you do not understand the fundamental difference between
ADS-B and FLARM.

ADS-B is designed for aircraft that do not want to fly close to each
other, and want/need long range situational awareness. Thats probably
where the whole ground station setup comes from - with all it's
disadvantages (coverage, latency, accuracy, etc.) It's a great system
for IFR traffic, and for GA flyers out sightseeing, but it sucks for
gliders in a gaggle or running a ridge.

FLARM, on the other hand, is specifically designed for aircraft
(gliders, helicopters) that often want to fly close to each other,
safely. In a gaggle, running a ridge, heading for the really nice Cu
near the glider field, on the Whites - gliders inherently will
congregate to find the best lift. That is the threat environment
FLARM is designed to cope with. And it's a proven item.

In a perfect world, there would be a SuperFLARM that would add some
sort of ADS-B in/out capability, so the benefits of both would be
present. But until then, FLARM addresses the immediate concern of
many, if not most glider pilots the best. A PowerFLARM, combined with
a mode s transponder, gives a glider most of the useful threat warning
capability of a full up ADS-B setup, and all the advantages of FLARM -
if FLARM is widely adopted by the US soaring community.

But if no-one gets ADS-b in their gliders (show of hands out there?),
then it's of no use in preventing the biggest historical threat -
glider on glider collisions.

I'm planning on getting a PowerFLARM next season to replace my PCAS.
I hope you will to, while waiting for your ADS-B to be installed.

Kirk
66

Mike Schumann

October 29th 10, 06:14 PM

On 10/29/2010 11:37 AM, kirk.stant wrote:
> Mike, I think you do not understand the fundamental difference between
> ADS-B and FLARM.
>
> ADS-B is designed for aircraft that do not want to fly close to each
> other, and want/need long range situational awareness. Thats probably
> where the whole ground station setup comes from - with all it's
> disadvantages (coverage, latency, accuracy, etc.) It's a great system
> for IFR traffic, and for GA flyers out sightseeing, but it sucks for
> gliders in a gaggle or running a ridge.
>
> FLARM, on the other hand, is specifically designed for aircraft
> (gliders, helicopters) that often want to fly close to each other,
> safely. In a gaggle, running a ridge, heading for the really nice Cu
> near the glider field, on the Whites - gliders inherently will
> congregate to find the best lift. That is the threat environment
> FLARM is designed to cope with. And it's a proven item.
>
> In a perfect world, there would be a SuperFLARM that would add some
> sort of ADS-B in/out capability, so the benefits of both would be
> present. But until then, FLARM addresses the immediate concern of
> many, if not most glider pilots the best. A PowerFLARM, combined with
> a mode s transponder, gives a glider most of the useful threat warning
> capability of a full up ADS-B setup, and all the advantages of FLARM -
> if FLARM is widely adopted by the US soaring community.
>
> But if no-one gets ADS-b in their gliders (show of hands out there?),
> then it's of no use in preventing the biggest historical threat -
> glider on glider collisions.
>
> I'm planning on getting a PowerFLARM next season to replace my PCAS.
> I hope you will to, while waiting for your ADS-B to be installed.
>
>
> Kirk
> 66

I think that you have a fundamental misunderstanding of ADS-B. ADS-B is
a general purpose system that is designed to permit aircraft to announce
their position and velocity vectors to anyone who is interested. For
all practical purposes, it has the same accuracy, latency, etc. of FLARM
based systems. It doesn't make any difference if aircraft are flying in
close proximity or not.

FLARM does the same thing and then adds another layer of collision
detection logic on top of that, which is specifically optimized for the
glider world. There is no reason that the same logic could not also be
added on-top of an ADS-B based position sensing technology. In fact,
PowerFLARM claims to be doing this using their 1090ES IN capability, if
the user has ADS-B Out installed.

The ground station ADS-B infrastructure is being deployed for 4 reasons:

1. To provide translation of ADS-B transmissions between UAT and 1090ES
(an unfortunate necessity due to the FAA's decision to go with 2 ADS-B
formats in the US)

2. To transmit TIS-B data. This lets ADS-B IN equipped aircraft see
the position and altitude of Mode C and S Transponder equipped aircraft
which are not yet outfitted with ADS-B transmitters.

3. To transmit additional weather and NOTAM information.

4. To detect ADS-B equipped aircraft so that they can be displayed on
ATC radar displays.

--
Mike Schumann

kirk.stant

October 29th 10, 06:33 PM

Mike, you have just confirmed what I just suspected. Again, ADS-b is
designed for keeping airplanes that want to stay apart, apart. And
yes, I understand exactly what the ground infrastructure is for, and
it's not gliders - It's for IFR air traffic control and GA planes
working their way through bad weather, checking on the latest NOTAMs
at their destination. Sure, "someone" could develop software and
hardware to use ADS-b to do what FLARM has been doing for the past 10
years, BUT THE CHANCE OF THAT HAPPENING IN THE NEAR FUTURE IS A CLOSE
APPROXIMATION OF ZERO!

Can't you understand that this isn't a zero sum game? NOTHING
prevents you from having FLARM now (in Europe) or next year (in the
US, hopefully) and later, if and when ADS-b becomes affordable and
useable in a glider cockpit, installing ADS-b in their glider. And
that even if the FAA gave a free UAT to every aircraft out there,
FLARM would still be useful in the glider community?

The two systems overlap each other, but occupy different requirement
niches.

Kirk
66

Darryl Ramm

October 29th 10, 06:46 PM

On Oct 29, 9:00*am, wrote:
> On 10/29/2010 11:16 AM, Mike Schumann wrote:
>
> > If the fundamental focus had been on affordability, there is no reason
> > that we couldn't now have commercial ADS-B equipment at the same price
> > points as FLARM units.
>
> NavWorx announced on Wednesday Oct. 27 that they are currently shipping
> the ADS600B transceivers.
> They offer their informal solution to the FAA's STC and/or TSO mandates
>
> > can be installed on both experimental and certified aircraft when it meets “portable installation guidelines.”<
>
>

I think we need to be fairly cautious parsing marketing talk.

On the page at http://www.navworx.com/myths.asp NavWorx is trying to
handle what they probably see as an wide negative view on ADS-B
adoption now from lots of commentators and organizations like AOPA,
authors in Flying Magazine, etc. Probably not what NavWorx intended
but having a read of all the links/comments they give there provides a
pretty good summary of the current negative-side view of ADS-B
adoption.

The reference above was to this statement from NavWorx...

"FAA memo mandates that all ADS-B equipment must be installed via STC
and meet TSO-C166b or TSO-C154c. NavWorx is compliant with TSO-C154c
providing both TIS-B and FIS-B. NavWorx equipment is available today
and can be installed on both experimental and certified aircraft when
it meets “portable installation guidelines.”"

Lets parse the two important bits of that statements carefully

**NavWorx [products] are compliant with TSO-C154c**

That is not saying the products are manufacted under TSO approval,
they are not. But there is often ambigious language in FARs about
whether a product needs to be manufactured under TSO approval or just
"Meets the requirements in TSO–xxx" to be installed. The later is the
case in FAR 91.225 that governs ADS-B carriage requirements. So
technically for a certified aircraft that leaves the A&P and maybe
FSDO to try to work out how to determine if something "Meets the
requirements in TSO–xxx" but is not yet TSO approved. If it gets to
the FSDO we can probably guess what their answer will be most of the
time. But with the current STC requirement policy from the FAA there
are no field approvals for installation of any ADS-B data-out
equipment on any certified aircraft (an STC cannot apply to an
experimental aircraft). And the FAA is extremely unlikely to approve
an STC that involved non actual-TSO approved ADS-B data-out equipment,
but like I've said before I really hope that work can be done in
parallel. It would be a very "brave" A&P who now tried to justify an
ADS-B data-out install as a minor modification to avoid doing even a
337.

Now the STC requirement is just an FAA approvals policy not a
regulation. (You can read it here
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgPolicy.nsf/0/34a9674f068fb64d86257790006d038a/$FILE/Approval%20for%20ADS-B%20Out%20Systems.pdf).
The FAA could change policy tomorrow. They could let any non-IFR
aircraft use field approval, they could let any glider use field
approval. It might be reasonable for the industry to try to work with
the FAA to more aggressively shorten the time those kind of aircraft
require STC for installations.

***NavWorx equipment is available today and can be installed on both
experimental and certified aircraft when it meets “portable
installation guidelines.***

No argument on NavWorx's claim here about "experimental aircraft", I
beleive they can have Navworx equipment, both their ADS-B receive only
and ADS-B transceiver equipment installed.

You cannot install an ADS-B data-out system that required connection
to an aircraft static source and installation of transmitter antennas
and call it a "portable install". NavWorx also makes portable UAT data-
in (receive only) products and I parse their statement here as "well
if you can't install one of our UAT transceivers because of this STC
requirement in a certified aircraft then you can at least install one
of our UAT receivers and still get some ADS_B benefits". Remember they
are only saying "equipment". Misquoting what's his name: It depends on
what the meaning of "equipment" is.

As a reminder UAT data-in is only suitable receiving UAT direct
broadcasts from UAT data-out equipped aircraft and FIS-B (weather and
Notam etc. data). A UAT data-in receiver cannot receive ADS-R or FIS-B
reliably unless you have an UAT data-out transmitter in the aircraft,
or combined in a transceiver. BTW -- I would have said ADS-B data-out
in general there before which is technically correct but the FAA also
seems to be discouraging mixed UAT data-out and 1090ES data-in or visa-
versa installations, and not that they can regulate what portable
receiver devices you install if you want to but I want to know more
why the FAA believes this is important enough to caution against.

For the GA market it would be great if ADS-B vendors could talk about
the actual STCs they are working on for installation in certified
aircraft. But I expect they see that as a competitive secret. I'd like
the FAA to talk about how long they expect the STC requirement to
remain in place and/or (since picking a time my be impossible) some of
the milestones they want to see before lifting this requirement in the
hope that may help the industry work though this.

Again this stuff only applies to certified aircraft. Experimental
aircraft are free to install the NavWorx and other ADS-B data-out
devices. The caution there for GA aircraft is if that installation is
going to be used to meet the carriage mandate in
FAR 91.225 they _may_ need to do extra work (e.g. on use a fancy WAAS
GPS driving the data-out).

And remember the NavWorx transceivers are not practical for
isntallation in gliders today, they consume too much power and don't
interface to any popular glider traffic displays and other issues I've
flogged to death before here.

----

BTW to be clear as well on all these FIS-B and TIS-B services. They
currently should be available in (mopstly) east and west coast ARTCC
regions as a part of the essential services (TIS-B and FIS-B (Weather,
NOTAMS etc.) enroute rollout but integration for most TRACON/Terminal
infrastructure will not happen until through 2013. So check with your
local TRACON for when exactly they will have essential (FIS-B, TIS-B)
and critical (ADS-R and ATC surveillance) service available.
Unfortunately there seems no good FAA or ITT website that provides
schedules in a understandable format (if anybody knows one I'd love to
know). It seems some pilots are interpreting some information
available on-line as many regions have full ADS-B essential (TIS-B and
FIS-B)and critical (ATC surveillance and ADS-R) services available in
both enroute and terminal service areas.

Darryl

Darryl Ramm

October 29th 10, 07:17 PM

On Oct 29, 8:16*am, Mike Schumann >
wrote:
> On 10/28/2010 10:21 PM, Darryl Ramm wrote:
[snip]
>
> You are confusing ADS-B and everything else under the "Nextgen" umbrella.

No. I am pointing out lots of the complexity in ADS-B comes from its
multiple applications for multiple different users seeking multiple
different benefits. Nextgen is the raison d'être for ADS-B and Nextgen
requirements have driven development of the underlying RTCA standards
etc.

> ADS-B is fundamentally a very simple concept. *You have a GPS in your
> airplane, and once a second you transmit your position and velocity
> vector data. *On the receive side, you listen and receive everyone
> else's position. *Additional data may also be available if you are
> interested (weather, Notams, etc.).

Ah now I get it I'm looking at this all wrong. I'm trying to look at
things from a practical, what works, how it works, what can be used
together viewpoint... for now and in the future. But what we should be
focusing on instead is simple concepts--even when any cogent practical
thought shows the actual use of these technologies in actual scenarios
to save actual pilots lives is not simple.

Why don't you write those simple concepts down on a sheet of paper and
tape them inside your cockpit. That will draw no power, require no
space to install, require no third party display devices, have no
false alarm issue, have no compatibility requirements with current
glider equipment and require no FAA approval. And should the small
practical things happen of you get killed in a mid-air collision we
can tape those simple concepts inside your coffin.

> ADS-B is basically the same as FLARM, except that FLARM also includes
> collision avoidance features that need to be implemented externally to
> the ADS-B transceiver, if the user desires this...

ADS-B is basically the same as FLARM for the purposes of making silly
debating points. The focus of most of the rest of us is what can most
practically/best be done to avoid mid-air collisions.

Darryl

Mike Schumann

October 29th 10, 07:30 PM

On 10/29/2010 12:33 PM, kirk.stant wrote:
> Mike, you have just confirmed what I just suspected. Again, ADS-b is
> designed for keeping airplanes that want to stay apart, apart. And
> yes, I understand exactly what the ground infrastructure is for, and
> it's not gliders - It's for IFR air traffic control and GA planes
> working their way through bad weather, checking on the latest NOTAMs
> at their destination. Sure, "someone" could develop software and
> hardware to use ADS-b to do what FLARM has been doing for the past 10
> years, BUT THE CHANCE OF THAT HAPPENING IN THE NEAR FUTURE IS A CLOSE
> APPROXIMATION OF ZERO!
>
> Can't you understand that this isn't a zero sum game? NOTHING
> prevents you from having FLARM now (in Europe) or next year (in the
> US, hopefully) and later, if and when ADS-b becomes affordable and
> useable in a glider cockpit, installing ADS-b in their glider. And
> that even if the FAA gave a free UAT to every aircraft out there,
> FLARM would still be useful in the glider community?
>
> The two systems overlap each other, but occupy different requirement
> niches.
>
>
> Kirk
> 66

The ground infrastructure is for EVERYONE! Glider pilots are probably
not as interested in weather or NOTAMs. They are interested in seeing
Mode C / S equipped aircraft (both GA and Jets) in their vicinity. This
is the BIG reason you should care about ADS-B ground stations.

The PowerFLARM proponents claim that it will handled 1090ES ADS-B
Inputs. Does this include TIS-B data? What is the plan for PowerFLARM
equipped aircraft to transmit ADS-B Out data so that the TIS-B data is
visible? If PowerFLARM can do that, then it will be a killer product,
not just for the glider world, but also for GA in the US.

--
Mike Schumann

Darryl Ramm

October 29th 10, 08:51 PM

On Oct 29, 11:30*am, Mike Schumann >
wrote:
> On 10/29/2010 12:33 PM, kirk.stant wrote:
>
>
>
> > Mike, you have just confirmed what I just suspected. *Again, ADS-b is
> > designed for keeping airplanes that want to stay apart, apart. *And
> > yes, I understand exactly what the ground infrastructure is for, and
> > it's not gliders - It's for IFR air traffic control and GA planes
> > working their way through bad weather, checking on the latest NOTAMs
> > at their destination. Sure, "someone" could develop software and
> > hardware to use ADS-b to do what FLARM has been doing for the past 10
> > years, BUT THE CHANCE OF THAT HAPPENING IN THE NEAR FUTURE IS A CLOSE
> > APPROXIMATION OF ZERO!
>
> > Can't you understand that this isn't a zero sum game? *NOTHING
> > prevents you from having FLARM now (in Europe) or next year (in the
> > US, hopefully) and later, if and when ADS-b becomes affordable and
> > useable in a glider cockpit, installing ADS-b in their glider. *And
> > that even if the FAA gave a free UAT to every aircraft out there,
> > FLARM would still be useful in the glider community?
>
> > The two systems overlap each other, but occupy different requirement
> > niches.
>
> > Kirk
> > 66
>
> The ground infrastructure is for EVERYONE! *Glider pilots are probably
> not as interested in weather or NOTAMs. *They are interested in seeing
> Mode C / S equipped aircraft (both GA and Jets) in their vicinity. *This
> is the BIG reason you should care about ADS-B ground stations.
>
> The PowerFLARM proponents claim that it will handled 1090ES ADS-B
> Inputs. *Does this include TIS-B data? *What is the plan for PowerFLARM
> equipped aircraft to transmit ADS-B Out data so that the TIS-B data is
> visible? *If PowerFLARM can do that, then it will be a killer product,
> not just for the glider world, but also for GA in the US.
>
> --
> Mike Schumann

Ground infrastructure, once it is deployed and in-service, is for
everybody within the coverage volume of that infrastructure and who is
properly equipped to use it. Unfortunately those requirements will
exclude many gliders and popular glider locations which may makes it
less useful than the combination of Flarm (esp. for glider threats)
and PCAS (esp. for GA threats) in PowerFLARM for many of us - assuming
we can get good mutual equipage of Flarm products within the glider
community. But that seems off to a good start.

As has been discussed on r.a.s. already Flarm have talked about
PowerFLARM having a software update in 2011 that will support TIS-B.
Since this is of any interest in the USA only, requires currently
expensive and difficult to install ADS-B data-out equipment, and TIS-B
capability has limited deployment today I hope Flarm does not waste
any time working on TIS-B support before the product ships. It is easy
to understand why TIS-B needs more work - TIS-B service data has
relatively high positional uncertainty compared to Flarm or ADS-B
direct data because the target information is from an SSR radar (or
multilateration) source and radar scan time delays and position
extrapolation induced errors. Some traffic displays might well just
ignore all this and treat the position of a TIS-B threat as if it is
highly precise and that could be a problem when you get close.... who
knows how all those third party PDA traffic display/processor devices
handle this today. I expect with Flarms focus on the glider market
they will work to get this right for our use.

To see threat aircraft via TIS-B the GBT ground infrastructure needs
to be deployed and integrated into the appropriate enroute and
terminal radar facilities and the threat aircraft need to to be within
that SSR radar coverage and your glider needs to be equipped with ADS-
B data-out (so the ADS-B ground infrastructure knows you are there)
and you obviously need some form of ADS-B data-in and TIS-B capable
traffic display/threat processing (PowerFLARM will do the later two
after the software update). If you do all that you will "see" TIS-B
data for all transponder equipped threats within +/-3,500' and a 15nm
cylinder around your aircraft's position. You may also see other TIS-B
"threats" within service volumes around other ADS-B data-out equipped
"client" aircraft but pilots really must not rely on that. I point it
out to explain to people why you may see a TIS-B threat on an ADS-B
data-in only system and that threat may magically appear and dissapear
from the display (but still be a very real threat)--if that happens
with PowerFLARM when used without ADS-B data-out at least the PCAS
should be screaming at you as the threat gets close.

TIS-B requires the deployment of FAA ground infrasttucutre and
integration of that with the appropriate radar facilities (enroute and
terminal facilities are rolled out differently). That won't be
complete for several more years. Pilots need to understand the
situation for their local area -- is TIS-B available and from enroute
and/or terminal radar and what are the coverage volumes for those
services.

I have no doubt that the directional and longer range capabilites of
TIS-B compared to PCAS is a nice thing. But given the current cost and
other issues around equipping with ADS-B data-out as well as ADS-B
data-in to receive TIS-B service makes this impractical at least for
the near future for most glider pilots. Most of my time talking with
pilots about TIS-B is to correct misunderstandings they have, for
example assuming that ADS-B data-in alone will provide TIS-B in their
cockpit.

Given the limited SSR coverage in many places we fly gliders and lack
of GBT (ADS-B ground based transceiver) coverage at many GA airports
and many popular gliding locations I do not see TIS-B as a replacement
for PCAS. I've seen lots of alerts on my Zaon MRX when definitively
outside of SSR coverage (presumably those transponders were being
interrogated by TCAS/TCAD equipped aircraft). A bit of the irony then
is that the PowerFLARM by being 1090ES not UAT based can easily
include PCAS capability and if a pilots wants to install 1090ES data-
out in future (as prices fall, products become more practical and
installation issues go away as they will) then that is a great
option.

Also just to point out a timing issue -- worrying about TIS-B for
gliders only makes sense if adoption becomes important within a
certain time window - for most after ~2013 as widescale TIS-B service
infrastructure deploy but before 2020 since after that TIS-B service
is expcted be turned off since the assumption is it won't be needed as
all those transponder equipped aircraft will be transmitting ADS-B
data-out and link-layer conversion vis ADS-R will provide all that is
needed. ADS-R will provide wider area and more accurate coverage than
TIS-B. I hope cost and install issues do decrease - I want to play
with all this with 1090ES data-out from a Trig TT21 in my (certified)
glider with PowerFLARM doing 1090ES data-in.

In discussing ADS-B ground infrastructure being "for everybody" it is
also worth noting that most deployments of ADS-B ground infrastructure
in the USA today do not include the ADS-R service yet and this
"critical service" (in FAA speak) will take several more years to roll
out widely. So if you have a UAT receiver you won't see any of those
1090ES data-out equipped airliners etc. who are amongst the early ADS-
B data-out adopters and of interest to many of us in location like
Reno. With a PowerFLARM with 1090ES data-in we see those directly, but
similarly those of us with PowerFLARM and its 1090ES data-in won't see
anybody with UAT data-out (until the ADS-R service is locally
available and then only when we are within coverage of the GBT - and
that will have significant coverage gaps for us to worry about,
especially close to terrain).

Again with any complex system like this the devil is in the practical
details...

Darryl

Mike Schumann

October 29th 10, 10:24 PM

On 10/29/2010 2:51 PM, Darryl Ramm wrote:
> On Oct 29, 11:30 am, Mike >
> wrote:
>> On 10/29/2010 12:33 PM, kirk.stant wrote:
>>
>>
>>
>>> Mike, you have just confirmed what I just suspected. Again, ADS-b is
>>> designed for keeping airplanes that want to stay apart, apart. And
>>> yes, I understand exactly what the ground infrastructure is for, and
>>> it's not gliders - It's for IFR air traffic control and GA planes
>>> working their way through bad weather, checking on the latest NOTAMs
>>> at their destination. Sure, "someone" could develop software and
>>> hardware to use ADS-b to do what FLARM has been doing for the past 10
>>> years, BUT THE CHANCE OF THAT HAPPENING IN THE NEAR FUTURE IS A CLOSE
>>> APPROXIMATION OF ZERO!
>>
>>> Can't you understand that this isn't a zero sum game? NOTHING
>>> prevents you from having FLARM now (in Europe) or next year (in the
>>> US, hopefully) and later, if and when ADS-b becomes affordable and
>>> useable in a glider cockpit, installing ADS-b in their glider. And
>>> that even if the FAA gave a free UAT to every aircraft out there,
>>> FLARM would still be useful in the glider community?
>>
>>> The two systems overlap each other, but occupy different requirement
>>> niches.
>>
>>> Kirk
>>> 66
>>
>> The ground infrastructure is for EVERYONE! Glider pilots are probably
>> not as interested in weather or NOTAMs. They are interested in seeing
>> Mode C / S equipped aircraft (both GA and Jets) in their vicinity. This
>> is the BIG reason you should care about ADS-B ground stations.
>>
>> The PowerFLARM proponents claim that it will handled 1090ES ADS-B
>> Inputs. Does this include TIS-B data? What is the plan for PowerFLARM
>> equipped aircraft to transmit ADS-B Out data so that the TIS-B data is
>> visible? If PowerFLARM can do that, then it will be a killer product,
>> not just for the glider world, but also for GA in the US.
>>
>> --
>> Mike Schumann
>
> Ground infrastructure, once it is deployed and in-service, is for
> everybody within the coverage volume of that infrastructure and who is
> properly equipped to use it. Unfortunately those requirements will
> exclude many gliders and popular glider locations which may makes it
> less useful than the combination of Flarm (esp. for glider threats)
> and PCAS (esp. for GA threats) in PowerFLARM for many of us - assuming
> we can get good mutual equipage of Flarm products within the glider
> community. But that seems off to a good start.
>
> As has been discussed on r.a.s. already Flarm have talked about
> PowerFLARM having a software update in 2011 that will support TIS-B.
> Since this is of any interest in the USA only, requires currently
> expensive and difficult to install ADS-B data-out equipment, and TIS-B
> capability has limited deployment today I hope Flarm does not waste
> any time working on TIS-B support before the product ships. It is easy
> to understand why TIS-B needs more work - TIS-B service data has
> relatively high positional uncertainty compared to Flarm or ADS-B
> direct data because the target information is from an SSR radar (or
> multilateration) source and radar scan time delays and position
> extrapolation induced errors. Some traffic displays might well just
> ignore all this and treat the position of a TIS-B threat as if it is
> highly precise and that could be a problem when you get close.... who
> knows how all those third party PDA traffic display/processor devices
> handle this today. I expect with Flarms focus on the glider market
> they will work to get this right for our use.
>
> To see threat aircraft via TIS-B the GBT ground infrastructure needs
> to be deployed and integrated into the appropriate enroute and
> terminal radar facilities and the threat aircraft need to to be within
> that SSR radar coverage and your glider needs to be equipped with ADS-
> B data-out (so the ADS-B ground infrastructure knows you are there)
> and you obviously need some form of ADS-B data-in and TIS-B capable
> traffic display/threat processing (PowerFLARM will do the later two
> after the software update). If you do all that you will "see" TIS-B
> data for all transponder equipped threats within +/-3,500' and a 15nm
> cylinder around your aircraft's position. You may also see other TIS-B
> "threats" within service volumes around other ADS-B data-out equipped
> "client" aircraft but pilots really must not rely on that. I point it
> out to explain to people why you may see a TIS-B threat on an ADS-B
> data-in only system and that threat may magically appear and dissapear
> from the display (but still be a very real threat)--if that happens
> with PowerFLARM when used without ADS-B data-out at least the PCAS
> should be screaming at you as the threat gets close.
>
> TIS-B requires the deployment of FAA ground infrasttucutre and
> integration of that with the appropriate radar facilities (enroute and
> terminal facilities are rolled out differently). That won't be
> complete for several more years. Pilots need to understand the
> situation for their local area -- is TIS-B available and from enroute
> and/or terminal radar and what are the coverage volumes for those
> services.
>
> I have no doubt that the directional and longer range capabilites of
> TIS-B compared to PCAS is a nice thing. But given the current cost and
> other issues around equipping with ADS-B data-out as well as ADS-B
> data-in to receive TIS-B service makes this impractical at least for
> the near future for most glider pilots. Most of my time talking with
> pilots about TIS-B is to correct misunderstandings they have, for
> example assuming that ADS-B data-in alone will provide TIS-B in their
> cockpit.
>
> Given the limited SSR coverage in many places we fly gliders and lack
> of GBT (ADS-B ground based transceiver) coverage at many GA airports
> and many popular gliding locations I do not see TIS-B as a replacement
> for PCAS. I've seen lots of alerts on my Zaon MRX when definitively
> outside of SSR coverage (presumably those transponders were being
> interrogated by TCAS/TCAD equipped aircraft). A bit of the irony then
> is that the PowerFLARM by being 1090ES not UAT based can easily
> include PCAS capability and if a pilots wants to install 1090ES data-
> out in future (as prices fall, products become more practical and
> installation issues go away as they will) then that is a great
> option.
>
> Also just to point out a timing issue -- worrying about TIS-B for
> gliders only makes sense if adoption becomes important within a
> certain time window - for most after ~2013 as widescale TIS-B service
> infrastructure deploy but before 2020 since after that TIS-B service
> is expcted be turned off since the assumption is it won't be needed as
> all those transponder equipped aircraft will be transmitting ADS-B
> data-out and link-layer conversion vis ADS-R will provide all that is
> needed. ADS-R will provide wider area and more accurate coverage than
> TIS-B. I hope cost and install issues do decrease - I want to play
> with all this with 1090ES data-out from a Trig TT21 in my (certified)
> glider with PowerFLARM doing 1090ES data-in.
>
> In discussing ADS-B ground infrastructure being "for everybody" it is
> also worth noting that most deployments of ADS-B ground infrastructure
> in the USA today do not include the ADS-R service yet and this
> "critical service" (in FAA speak) will take several more years to roll
> out widely. So if you have a UAT receiver you won't see any of those
> 1090ES data-out equipped airliners etc. who are amongst the early ADS-
> B data-out adopters and of interest to many of us in location like
> Reno. With a PowerFLARM with 1090ES data-in we see those directly, but
> similarly those of us with PowerFLARM and its 1090ES data-in won't see
> anybody with UAT data-out (until the ADS-R service is locally
> available and then only when we are within coverage of the GBT - and
> that will have significant coverage gaps for us to worry about,
> especially close to terrain).
>
> Again with any complex system like this the devil is in the practical
> details...
>
> Darryl

What evidence do you have that there are plans to turn off TIS-B after
2020? The current 2020 ADS-B out rules only require equipage in certain
airspace environments. There are lots of areas where there will be
ADS-B ground station and radar coverage, where ADS-B out equipage will
be optional, and there may be a significant number of Mode C/S
transponder equipped GA aircraft still flying around without ADS-B.

While there are a lot of remote areas of the country where TIS-B will
not be available to glider pilots, there are also a lot of areas close
to metro areas where a lot of recreational pilots fly where ADS-B ground
stations with TIS-B support are or will be turned on a lot quicker than
you are leading people to believe.

I would certainly encourage the PowerFLARM people to figure out how to
support TIS-B as quickly as possible (which of course will require them
to figure out a practical, cost effective way for pilots to add ADS-B
Out equipment to their cockpits). If this becomes a practical product
feature, it would be a huge advance over PCAS and would open up the GA
market to their system, which is 10x larger than the glider market in
the US.

--
Mike Schumann

kirk.stant

October 29th 10, 10:27 PM

Darryl, by the way, the USAF (and I assume USN/Marines/Army) is in the
process of installing Mode S (with 1090 ES) in many (if not all) of
it's planes. C-17s are already using this mode in Europe, as can be
seen on the sites that show Mode S tracks. And I personally know that
F-15Es are being equipped with Mode S.

What this means is that there is the potential for using the
PowerFLARM 1090 ES detection capability to provide accurate and timely
warning of military aircraft - such as fighters on low level routes,
and in MOAs. That would be awesome - I'm sure we have all been
surprised by a pair of fighters at some time.

What we may need is for SSA to push the DOD to require all military
aircraft equipped with Mode S transponders to use them at all times
when practicable and explain why.

This capability in itself makes a PowerFLARM a necessity in some
areas!

Cheers,

Kirk

vaughn[_3_]

October 29th 10, 10:53 PM

"Mike Schumann" > wrote in message
...
> What evidence do you have that there are plans to turn off TIS-B after 2020?
Some TIS stations are already gone. See this AOPA blurb:
http://www.aopa.org/whatsnew/newsitems/2005/051101tis.html Google for more.

Vaughn

Darryl Ramm

October 29th 10, 11:11 PM

On Oct 29, 2:24*pm, Mike Schumann >
wrote:
> On 10/29/2010 2:51 PM, Darryl Ramm wrote:
>
>
>
> > On Oct 29, 11:30 am, Mike >
> > wrote:
> >> On 10/29/2010 12:33 PM, kirk.stant wrote:
>
> >>> Mike, you have just confirmed what I just suspected. *Again, ADS-b is
> >>> designed for keeping airplanes that want to stay apart, apart. *And
> >>> yes, I understand exactly what the ground infrastructure is for, and
> >>> it's not gliders - It's for IFR air traffic control and GA planes
> >>> working their way through bad weather, checking on the latest NOTAMs
> >>> at their destination. Sure, "someone" could develop software and
> >>> hardware to use ADS-b to do what FLARM has been doing for the past 10
> >>> years, BUT THE CHANCE OF THAT HAPPENING IN THE NEAR FUTURE IS A CLOSE
> >>> APPROXIMATION OF ZERO!
>
> >>> Can't you understand that this isn't a zero sum game? *NOTHING
> >>> prevents you from having FLARM now (in Europe) or next year (in the
> >>> US, hopefully) and later, if and when ADS-b becomes affordable and
> >>> useable in a glider cockpit, installing ADS-b in their glider. *And
> >>> that even if the FAA gave a free UAT to every aircraft out there,
> >>> FLARM would still be useful in the glider community?
>
> >>> The two systems overlap each other, but occupy different requirement
> >>> niches.
>
> >>> Kirk
> >>> 66
>
> >> The ground infrastructure is for EVERYONE! *Glider pilots are probably
> >> not as interested in weather or NOTAMs. *They are interested in seeing
> >> Mode C / S equipped aircraft (both GA and Jets) in their vicinity. *This
> >> is the BIG reason you should care about ADS-B ground stations.
>
> >> The PowerFLARM proponents claim that it will handled 1090ES ADS-B
> >> Inputs. *Does this include TIS-B data? *What is the plan for PowerFLARM
> >> equipped aircraft to transmit ADS-B Out data so that the TIS-B data is
> >> visible? *If PowerFLARM can do that, then it will be a killer product,
> >> not just for the glider world, but also for GA in the US.
>
> >> --
> >> Mike Schumann
>
> > Ground infrastructure, once it is deployed and in-service, is for
> > everybody within the coverage volume of that infrastructure and who is
> > properly equipped to use it. Unfortunately those requirements will
> > exclude many gliders and popular glider locations which may makes it
> > less useful than the combination of Flarm (esp. for glider threats)
> > and PCAS (esp. for GA threats) in PowerFLARM for many of us - assuming
> > we can get good mutual equipage of Flarm products within the glider
> > community. But that seems off to a good start.
>
> > As has been discussed on r.a.s. already Flarm have talked about
> > PowerFLARM having a software update in 2011 that will support TIS-B.
> > Since this is of any interest in the USA only, requires currently
> > expensive and difficult to install ADS-B data-out equipment, and TIS-B
> > capability has limited deployment today I hope Flarm does not waste
> > any time working on TIS-B support before the product ships. It is easy
> > to understand why TIS-B needs more work - TIS-B service data has
> > relatively high positional uncertainty compared to Flarm or ADS-B
> > direct data because the target information is from an SSR radar (or
> > multilateration) source and radar scan time delays and position
> > extrapolation induced errors. Some traffic displays might well just
> > ignore all this and treat the position of a TIS-B threat as if it is
> > highly precise and that could be a problem when you get close.... who
> > knows how all those third party PDA traffic display/processor devices
> > handle this today. I expect with Flarms focus on the glider market
> > they will work to get this right for our use.
>
> > To see threat aircraft via TIS-B the GBT ground infrastructure needs
> > to be deployed and integrated into the appropriate enroute and
> > terminal radar facilities and the threat aircraft need to to be within
> > that SSR radar coverage and your glider needs to be equipped with ADS-
> > B data-out (so the ADS-B ground infrastructure knows you are there)
> > and you obviously need some form of ADS-B data-in and TIS-B capable
> > traffic display/threat processing (PowerFLARM will do the later two
> > after the software update). If you do all that you will "see" TIS-B
> > data for all transponder equipped threats within +/-3,500' and a 15nm
> > cylinder around your aircraft's position. You may also see other TIS-B
> > "threats" within service volumes around other ADS-B data-out equipped
> > "client" aircraft but pilots really must not rely on that. I point it
> > out to explain to people why you may see a TIS-B threat on an ADS-B
> > data-in only system and that threat may magically appear and dissapear
> > from the display (but still be a very real threat)--if that happens
> > with PowerFLARM when used without ADS-B data-out at least the PCAS
> > should be screaming at you as the threat gets close.
>
> > TIS-B requires the deployment of FAA ground infrasttucutre and
> > integration of that with the appropriate radar facilities (enroute and
> > terminal facilities are rolled out differently). That won't be
> > complete for several more years. Pilots need to understand the
> > situation for their local area -- is TIS-B available and from enroute
> > and/or terminal radar and what are the coverage volumes for those
> > services.
>
> > I have no doubt that the directional and longer range capabilites of
> > TIS-B compared to PCAS is a nice thing. But given the current cost and
> > other issues around equipping with ADS-B data-out as well as ADS-B
> > data-in to receive TIS-B service makes this impractical at least for
> > the near future for most glider pilots. Most of my time talking with
> > pilots about TIS-B is to correct misunderstandings they have, for
> > example assuming that ADS-B data-in alone will provide TIS-B in their
> > cockpit.
>
> > Given the limited SSR coverage in many places we fly gliders and lack
> > of GBT (ADS-B ground based transceiver) coverage at many GA airports
> > and many popular gliding locations I do not see TIS-B as a replacement
> > for PCAS. I've seen lots of alerts on my Zaon MRX when definitively
> > outside of SSR coverage (presumably those transponders were being
> > interrogated by TCAS/TCAD equipped aircraft). A bit of the irony then
> > is that the PowerFLARM by being 1090ES not UAT based can easily
> > include PCAS capability and if a pilots wants to install 1090ES data-
> > out in future (as prices fall, products become more practical and
> > installation issues go away as they will) then that is a great
> > option.
>
> > Also just to point out a timing issue -- worrying about TIS-B for
> > gliders only makes sense if adoption becomes important within a
> > certain time window - for most after ~2013 as widescale TIS-B service
> > infrastructure deploy but before 2020 since after that TIS-B service
> > is expcted be turned off since the assumption is it won't be needed as
> > all those transponder equipped aircraft will be transmitting ADS-B
> > data-out and link-layer conversion vis ADS-R will provide all that is
> > needed. ADS-R will provide wider area and more accurate coverage than
> > TIS-B. I hope cost and install issues do decrease - I want to play
> > with all this with 1090ES data-out from a Trig TT21 in my (certified)
> > glider with PowerFLARM doing 1090ES data-in.
>
> > In discussing ADS-B ground infrastructure being "for everybody" it is
> > also worth noting that most deployments of ADS-B ground infrastructure
> > in the USA today do not include the ADS-R service yet and this
> > "critical service" (in FAA speak) will take several more years to roll
> > out widely. So if you have a UAT receiver you won't see any of those
> > 1090ES data-out equipped airliners etc. who are amongst the early ADS-
> > B data-out adopters and of interest to many of us in location like
> > Reno. With a PowerFLARM with 1090ES data-in we see those directly, but
> > similarly those of us with PowerFLARM and its 1090ES data-in won't see
> > anybody with UAT data-out (until the ADS-R service is locally
> > available and then only when we are within coverage of the GBT - and
> > that will have significant coverage gaps for us to worry about,
> > especially close to terrain).
>
> > Again with any complex system like this the devil is in the practical
> > details...
>
> > Darryl
>
> What evidence do you have that there are plans to turn off TIS-B after
> 2020? *The current 2020 ADS-B out rules only require equipage in certain
> airspace environments. *There are lots of areas where there will be
> ADS-B ground station and radar coverage, where ADS-B out equipage will
> be optional, and there may be a significant number of Mode C/S
> transponder equipped GA aircraft still flying around without ADS-B.
>
> While there are a lot of remote areas of the country where TIS-B will
> not be available to glider pilots, there are also a lot of areas close
> to metro areas where a lot of recreational pilots fly where ADS-B ground
> stations with TIS-B support are or will be turned on a lot quicker than
> you are leading people to believe.
>
> I would certainly encourage the PowerFLARM people to figure out how to
> support TIS-B as quickly as possible (which of course will require them
> to figure out a practical, cost effective way for pilots to add ADS-B
> Out equipment to their cockpits). *If this becomes a practical product
> feature, it would be a huge advance over PCAS and would open up the GA
> market to their system, which is 10x larger than the glider market in
> the US.
>
> --
> Mike Schumann

The FAA has long stated their desire to decommission TIS-B some time
after 2020. There were objections to this in the comments to the NPRM
and in the final ADS-B rule making document the FAA promised it "will
evaluate the benefits of continuing TIS–B past the 2020 rule
compliance date" but I parse that as a non-committal committal and I
believe from other information this is still the goal. If you have
different information please let us know.

Remember also the cost saving from decommissioning of some existing
primary radar and SSR infrastructure is a part of what is driving the
cost justification for the ADS-B part of Nextgen. So you would loose
those source of TIS-B input data. By no means is all that SSR
infrastructure being proposed for decommissioning, but enough terminal
coverage is likely to be removed to be significant. And it may be an
interesting political juggling act for the FAA to claim to want to
turn off significant SSR radar infrastructure on on hand and about in
parallel want to keep alive TIS-B than would need input from those
sources. I have concerns about the uncompromising of terminal primary
radar and SSR infrastructure both from a redundancy and domestic
airspace national security virewpoints.

I'm not trying to lead anybody to think anything about schedules,
beyond saying that full deployment is scheduled for 2013. The fact
alone that ADS-R is virtually non-existent is a surprise for most
pilots--an important issue. Pilots need to check locally for the
details of what and when services are being deployed they can use. I
don't think most pilots hear about ADS-B and think en-route vs.
terminal vs. essential services vs. critical service deployment but
again because all this is complex they need to be thinking about that.
But what is the point of arguing, your the biggest proponent of this
stuff being used in the short term--maybe you could help explain the
USA ADS-B roll-out/schedule (in practical detail not concept) to help
people make equipage decisions.

Darryl

Bart[_4_]

October 29th 10, 11:15 PM

On Oct 27, 7:45*am, Kevin Christner > wrote:
> You are confusing cause and effect. *Your CHOICE to take more risk
> CAUSES you to wear a parachute. *Your CHOICE to fly in competition
> will CAUSE (force) you to use a FLARM. *You made choices independent
> of equipment. *The equipment didnt cause you to take more risk.

A parachute strapped to my back may cause me to decide to spin down at
the end of a local soaring flight if I happen to have some altitude to
waste. Lack of a parachute will cause me to pull the brakes in such a
situation.

Just an example.

B.

Darryl Ramm

October 29th 10, 11:36 PM

On Oct 29, 2:53*pm, "vaughn" > wrote:
> "Mike Schumann" > wrote in message
>
> ...> What evidence do you have that there are plans to turn off TIS-B after 2020?
>
> Some TIS stations are already gone. See this AOPA blurb:http://www.aopa.org/whatsnew/newsitems/2005/051101tis.html*Google for more.
>
> Vaughn

Vaughn

Actual this is talking about Mode S TIS (sometimes incorrectly called
TIS-S). Which is not related to ADS-B TIS-B although some of the
concepts are similar. ("concepts" is my favorite work at the
moment...)

Mode S TIS is (or was if your local service has been decommissioned) a
great service used in the USA that uplinks terminal/approach radar
traffic information to a Mode S transponder capable of receiving TIS
data. (Yes Mode S transponders are fancy enough the can receive uplink
data as well as downlink data, but the uplink is not the same as
1090ES data-in).

Mode S TIS transponder advertise to the approach radar that is has TIS
capability then the approach radar TIS processor calculates threats
within an ~8nm radius cylinder +/- 3k' or so (its actually more
complex than that but I'll spare you the pain) around the client
aircraft and uplinks that data to the client transponder (using
relative distance and direction). This requires you are within
coverage of a TIS equipped SSR terminal (not enroute) radar and you
have a Mode S transponder that supports TIS and it is connected to a
compatible display. Enroute radar can't provide TIS for multiple
reasons including the slow scan/update rates, traffic volumes, etc.

The Mode S TIS decommissioning issue was as the FAA upgraded some
terminal SSR systems they did not want to pay to add the TIS support
to those systems, even if the SSR radar they were upgrading had
previously had it. To me this was a very poor decision since Mode S
TIS was encouraging many GA aircraft to equip with traffic displays
and encouraging pilots to use traffic awareness systems - which would
have been a good segway into ADS-B. To rub salt into this the are some
realtively low-cost add-on Mode S TIS processor systems that use
omnidirectional antennas (the Mode S TIS data-uplink does not has to
go though the SSR radar directional antenna) that companies proposed
to the FAA and were turned down on. But in the FAA's defense here is
they are just a funding starved organization trying to do a lot. Maybe
too much, but that is debatable.

Around the places like the San Francisco Bay Area where I live Mode S
TIS still provides very useful traffic information to many GA
aircraft. The other advantage of Mode S TIS is is is relatively a low-
cost feature to add to any Mode S transponder. For example the pretty
standard Garmin GTX 33 and GTX 330 transponders come with it included.
The Trig TT21 that is being used in gliders also comes with Mode S TIS
-- but you need to connect it to display that support the "TIS serial
protocol" -- e.g. something like my Gamin 496 -- and that's the same
whole issue that the UAT and 1090ES receivers not designed for glider
cockpits have with not supporting the Flarm serial dataport protocol
that is widely supported by display products in our cockpits.

Darryl

Kevin Christner

October 30th 10, 12:18 AM

On Oct 29, 3:15*pm, Bart > wrote:
> On Oct 27, 7:45*am, Kevin Christner > wrote:
>
> > You are confusing cause and effect. *Your CHOICE to take more risk
> > CAUSES you to wear a parachute. *Your CHOICE to fly in competition
> > will CAUSE (force) you to use a FLARM. *You made choices independent
> > of equipment. *The equipment didnt cause you to take more risk.
>
> A parachute strapped to my back may cause me to decide to spin down at
> the end of a local soaring flight if I happen to have some altitude to
> waste. Lack of a parachute will cause me to pull the brakes in such a
> situation.
>
> Just an example.
>
> B.

Again the equipment did not cause you to take more risk. You chose to
spin down. The parachute didn't cause you to do it.

Just an example.

Darryl Ramm

October 30th 10, 02:37 AM

On Oct 29, 2:27*pm, "kirk.stant" > wrote:
> Darryl, by the way, the USAF (and I assume USN/Marines/Army) is in the
> process of installing Mode S (with 1090 ES) in many (if not all) of
> it's planes. *C-17s are already using this mode in Europe, as can be
> seen on the sites that show Mode S tracks. *And I personally know that
> F-15Es are being equipped with Mode S.
>
> What this means is that there is the potential for using the
> PowerFLARM 1090 ES detection capability to provide accurate and timely
> warning of military aircraft - such as fighters on low level routes,
> and in MOAs. *That would be awesome - I'm sure we have all been
> surprised by a pair of fighters at some time.
>
> What we may need is for SSA to push the DOD to require all military
> aircraft equipped with Mode S transponders to use them at all times
> when practicable and explain why.
>
> This capability in itself makes a PowerFLARM a necessity in some
> areas!
>
> Cheers,
>
> Kirk

Kirk

Thanks for the info.

BTW if you look at current goodies like the BAE F15 CIT it is a
combined Mode 4 IFF transponder *and* interrogator that also does Mode
S etc. i.e. it can interrogate a Mode C or Mode S transponder in your
glider and paint you on the tactical display and you can also see
their Mode S transponder. All assuming they want to let you see them
of course. See pdf brochure at http://tiny.cc/alo9f its a sexy piece
of technology. I believe that system is going into recent F15
refreshes.

Effectively all the heavy transports and tankers have Mode S, because
the USAF has equipped them with TCAS II systems with require Mode S in
the TCAS equipped aircraft (but will work with Mode C or Mode S in the
threat aircraft) and also probably for compatibility with ATC in
Europe and elsewhere. With Europe mandating 1090ES data out for
aircraft over 5,700kg it makes sense for large military transports to
equip with that even ahead of USA domestic requirements - even if the
military may be technically exempt from requirements. In any serious
threat situation that transponder and especially 1090ES data-out is
going to be turned off, they have "aim here" written all over them. It
will be interesting to see what military transports etc. do with ADS-B
data-in/CDTI to enhance TCAS II displays.

I agree that seeing both transport and fast military traffic via long-
range 1090ES data-in like that in the PowerFLARM could be very useful
- especially in knowing general areas where this traffic is operating.
But if military traffic is a major concern maybe a more effective
thing you can do is to equip with a Mode C or Mode S transponder.
Effectively all heavy military transports and tankers have TCAS II
equivalent that can see your transponder and provide RA instructions
to the crew, military controllers can see your transponder on their
SSR radar and many tactical aircraft equipped with radar/IFF can see
you transponder systems - *if* they have the IFF in the right
interrogator mode, which they might not in all situations. I would
talk to the flight ops or RAPCON etc. at the military facility about
their aircraft equipment and operating proceeds. I'd much rather have
ATC controllers, TCAS II and IFF systems keep us separated than rely
on doing something to avoid them at the last minute.

One of our local traffic concern are heavy transport and busy mixed GA
around Travis AFB and all that traffic effectively has TCAS II and the
local RAPCON sees all out transponder equipped gliders but is blind in
large areas due to radar scatter from windmills and cannot see any
primary glider targets. They provide great service, including flight
following to gliders and are very easy to work with. Oh yes and when
are all those USAF RAPCON getting ADS-B critical services so they can
see UAT equipped traffic (without transponders). Who knows, again my
head hurts too much thinking about that (OK I lied I'm asking around
on that one).

Darryl