Anti Collision Warning [Archive]

Ramy Yanetz

April 29th 04, 09:15 AM

See my other reply below. These devices should be capable to warn you of
imminent collision even while thermaling, not just warn you of nearby
aircraft. And if they currently don't, they will in the near future. It
should not be too difficult to compute collision courses.

Ramy

"tango4" > wrote in message
...
>
> "Ramy Yanetz" > wrote in message
> om...
> > Robert Ehrlich > wrote in message
> >...
> > Hopefully one day these devices will replace transponders on ALL
> > aircrafts and will be required on all aircrafts. Then the madness of
> > mid airs will end.
> >
> > Ramy
>
> No it wont! More than half of the midairs recently involved aircraft where
> the pilots were flying together, knew that the other aircraft was there
and
> *still* collided. All that anti collision systems would have added to
these
> situations would have been a bit of total aircraft mass.
>
> The problem we currently have is that in spite of knowing that other
> aircraft are very close by pilots are getting it wrong and banging in to
> each other.
>
> We need to review -
> Thermal joining techniques
> Thermal leaving techniques
> co-thermaling practices
> co-operative flying practice.
>
> Read Paul Adriance's account of his accident earlier this month, it wasn't
> caused by GPS or any other form of instrumentation, weather or anything
else
> and no form of instrumentation would have changed the outcome. The pilots
> simply lost situational awareness and in a few moments it all went very
> wrong.
>
> Ian
>
>
>

Andy Durbin

April 29th 04, 02:46 PM

(Ramy Yanetz) wrote in message
>
> These devices should be capable to tell you if you are in a collision
> course, not just warn you of a nearby aircraft. Earlier someone posted
> a link to a new device which also calculate collision course while
> thermaling! If you thermal too close to someone else it should warn
> you.

But how close is *too close*? I am perfectly comfortable cranked up
at a 50 deg bank with someone opposite me doing the same thing, but
very uncomfortable if another glider joins with the same separation
and puts me in their blind spot.

To be effective in providing warnings the device would have to
continuously predict collisions based not only on the current
trajectory of each aircraft, but also predict collisions based on all
possible future trajectories for the next say 30 seconds. Try
resolving that mess when there are 30+ gliders at the top of the same
thermal waiting for a contest start. The false alarm rate would be
unacceptable.

The nearest the US regulators have come to such a system is the
proposed ADS-B, but that seems to be a long way from the dream of 10
years ago that a GPS based ADS-B could be small and cheap enough to
be carried by ultralights and skydivers.

Andy (GY)

Eric Greenwell

April 29th 04, 04:10 PM

Andy Durbin wrote:
> (Ramy Yanetz) wrote in message
>
>>These devices should be capable to tell you if you are in a collision
>>course, not just warn you of a nearby aircraft. Earlier someone posted
>>a link to a new device which also calculate collision course while
>>thermaling! If you thermal too close to someone else it should warn
>>you.
>
>
>
> But how close is *too close*? I am perfectly comfortable cranked up
> at a 50 deg bank with someone opposite me doing the same thing, but
> very uncomfortable if another glider joins with the same separation
> and puts me in their blind spot.
>
> To be effective in providing warnings the device would have to
> continuously predict collisions based not only on the current
> trajectory of each aircraft, but also predict collisions based on all
> possible future trajectories for the next say 30 seconds. Try
> resolving that mess when there are 30+ gliders at the top of the same
> thermal waiting for a contest start. The false alarm rate would be
> unacceptable.

I think Andy is right, but I don't think that situation is the one that
produces the most collisions. My undocumented impression is the majority
involve just a few gliders, often just two. The computations for two or
three gliders should be easy compared to 6 or more. During thermalling
or beating back and forth on a ridge, gliders don't change relative
altitude very much, so this much reduces the potential paths.

So, a system that worked for 2 or 3 gliders would be useful, and as
experience was gained with it, I think it would be continually upgraded
to cover situations with more gliders. Even if it didn't work for more
than even 5 gliders, that would cover most situations.
--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

tango4

April 29th 04, 05:10 PM

Of course the problem is which 5 out of the 7 in a particular thermal do you
track?

:-)

Ian

"Eric Greenwell" > wrote in message
...
> Andy Durbin wrote:
> > (Ramy Yanetz) wrote in message
> >
> >>These devices should be capable to tell you if you are in a collision
> >>course, not just warn you of a nearby aircraft. Earlier someone posted
> >>a link to a new device which also calculate collision course while
> >>thermaling! If you thermal too close to someone else it should warn
> >>you.
> >
> >
> >
> > But how close is *too close*? I am perfectly comfortable cranked up
> > at a 50 deg bank with someone opposite me doing the same thing, but
> > very uncomfortable if another glider joins with the same separation
> > and puts me in their blind spot.
> >
> > To be effective in providing warnings the device would have to
> > continuously predict collisions based not only on the current
> > trajectory of each aircraft, but also predict collisions based on all
> > possible future trajectories for the next say 30 seconds. Try
> > resolving that mess when there are 30+ gliders at the top of the same
> > thermal waiting for a contest start. The false alarm rate would be
> > unacceptable.
>
> I think Andy is right, but I don't think that situation is the one that
> produces the most collisions. My undocumented impression is the majority
> involve just a few gliders, often just two. The computations for two or
> three gliders should be easy compared to 6 or more. During thermalling
> or beating back and forth on a ridge, gliders don't change relative
> altitude very much, so this much reduces the potential paths.
>
> So, a system that worked for 2 or 3 gliders would be useful, and as
> experience was gained with it, I think it would be continually upgraded
> to cover situations with more gliders. Even if it didn't work for more
> than even 5 gliders, that would cover most situations.
> --
> Change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
> USA
>

Marcel Duenner

April 29th 04, 07:07 PM

"Ramy Yanetz" > wrote in message >...
> See my other reply below. These devices should be capable to warn you of
> imminent collision even while thermaling, not just warn you of nearby
> aircraft. And if they currently don't, they will in the near future. It
> should not be too difficult to compute collision courses.
>

That is exactly what FLARM does.

303pilot

April 29th 04, 10:48 PM

"Eric Greenwell" > wrote in message
...
> Andy Durbin wrote:
> > (Ramy Yanetz) wrote in message
> >
> >>These devices should be capable to tell you if you are in a collision
> >>course, not just warn you of a nearby aircraft. Earlier someone posted
> >>a link to a new device which also calculate collision course while
> >>thermaling! If you thermal too close to someone else it should warn
> >>you.
> >
> >
> >
> > But how close is *too close*? I am perfectly comfortable cranked up
> > at a 50 deg bank with someone opposite me doing the same thing, but
> > very uncomfortable if another glider joins with the same separation
> > and puts me in their blind spot.
> >
> > To be effective in providing warnings the device would have to
> > continuously predict collisions based not only on the current
> > trajectory of each aircraft, but also predict collisions based on all
> > possible future trajectories for the next say 30 seconds. Try
> > resolving that mess when there are 30+ gliders at the top of the same
> > thermal waiting for a contest start. The false alarm rate would be
> > unacceptable.
>
> I think Andy is right, but I don't think that situation is the one that
> produces the most collisions. My undocumented impression is the majority
> involve just a few gliders, often just two. The computations for two or
> three gliders should be easy compared to 6 or more. During thermalling
> or beating back and forth on a ridge, gliders don't change relative
> altitude very much, so this much reduces the potential paths.
>
> So, a system that worked for 2 or 3 gliders would be useful, and as
> experience was gained with it, I think it would be continually upgraded
> to cover situations with more gliders. Even if it didn't work for more
> than even 5 gliders, that would cover most situations.
> --
> Change "netto" to "net" to email me directly
>
This still leaves the problem I think Andy was getting at of what is the
acceptable false positive:false negative ratio?
Too many false positives and pilots won't use it.
False negatives would lead to collisions, deaths and, at least in the US,
lawsuits that would likely put the manufacturer out of business.

Brent

Dave Martin

April 29th 04, 11:19 PM

Whatever happened to teaching good look out and airmanship?

David Starer

April 29th 04, 11:24 PM

Good for you! That's the best contribution to this thread I've seen.
David Starer

"Dave Martin" > wrote in message
...
> Whatever happened to teaching good look out and airmanship?
>
>
>
>

David Starer

April 29th 04, 11:28 PM

Good for you! That's the best contribution to this thread I've seen.
David Starer

"Dave Martin" > wrote in message
...
> Whatever happened to teaching good look out and airmanship?
>
>
>
>

Bill Daniels

April 29th 04, 11:32 PM

"303pilot" <brentUNDERSCOREsullivanATbmcDOTcom> wrote in message
...
> "Eric Greenwell" > wrote in message
> ...
> > Andy Durbin wrote:
> > > (Ramy Yanetz) wrote in message
> > >
> > >>These devices should be capable to tell you if you are in a collision
> > >>course, not just warn you of a nearby aircraft. Earlier someone posted
> > >>a link to a new device which also calculate collision course while
> > >>thermaling! If you thermal too close to someone else it should warn
> > >>you.
> > >
> > >
> > >
> > > But how close is *too close*? I am perfectly comfortable cranked up
> > > at a 50 deg bank with someone opposite me doing the same thing, but
> > > very uncomfortable if another glider joins with the same separation
> > > and puts me in their blind spot.
> > >
> > > To be effective in providing warnings the device would have to
> > > continuously predict collisions based not only on the current
> > > trajectory of each aircraft, but also predict collisions based on all
> > > possible future trajectories for the next say 30 seconds. Try
> > > resolving that mess when there are 30+ gliders at the top of the same
> > > thermal waiting for a contest start. The false alarm rate would be
> > > unacceptable.
> >
> > I think Andy is right, but I don't think that situation is the one that
> > produces the most collisions. My undocumented impression is the majority
> > involve just a few gliders, often just two. The computations for two or
> > three gliders should be easy compared to 6 or more. During thermalling
> > or beating back and forth on a ridge, gliders don't change relative
> > altitude very much, so this much reduces the potential paths.
> >
> > So, a system that worked for 2 or 3 gliders would be useful, and as
> > experience was gained with it, I think it would be continually upgraded
> > to cover situations with more gliders. Even if it didn't work for more
> > than even 5 gliders, that would cover most situations.
> > --
> > Change "netto" to "net" to email me directly
> >
> This still leaves the problem I think Andy was getting at of what is the
> acceptable false positive:false negative ratio?
> Too many false positives and pilots won't use it.
> False negatives would lead to collisions, deaths and, at least in the US,
> lawsuits that would likely put the manufacturer out of business.
>
> Brent
>
>

We can't ask for perfection or nothing will ever be available. It seems to
me that there are two indications we should be looking for in a basic
anti-collision device.

1, There are (n) gliders in close proximity - say 1 kilometer. Even simple
GPS broadcast devices should be able to determine the number of gliders
nearby. It should beep softly when the number changes. (If the device says
there are 3 gliders nearby and you can only see 2, you need to keep
looking.)

2, If one of these represents a collision danger, the device should give a
bearing. The device need only determine that the target is at or near the
same altitude, the distance is closing and the relative bearing is nearly
constant. If there is only 1% chance of an actual collision, that would get
my undivided attention.

Of course, collisions can occur with different geometry's but they are rare.

The device doesn't need to exactly predict a collision, only that one is
possible. That would be enough to get a pilots attention. There are a
couple a traffic alert/collision avoidance devices on the market now and
they don't seem too worried about legal troubles.

Commercial ADS-B devices will not be available for many years. The avionics
industry has to sell everybody a Mode S transponder first (Big$), THEN we
will get to upgrade to ADS-B(Still more big $). I hope these small efforts
within the soaring community produce something we all can use. We sure need
it.

Bill Daniels

Bill Daniels

April 29th 04, 11:38 PM

"Dave Martin" > wrote in message
...
> Whatever happened to teaching good look out and airmanship?
>
Long and sad experience says it doesn't always work. "Just look outside"
is often an excuse for doing nothing about the problem.

Bill Daniels

Snead1

April 30th 04, 03:10 AM

I have been playing with a pair of Garmin Rinhos. They are a combination GPS
and Family Radio Transceiver. They have the ability, at about $150 per unit,
to track other units and plot their positions. The presentation of the
relative positions is not good enough to use for collision avoidance in my
opinion, but the esentials are all there at a low price.

Bill Snead
6W

Graeme Cant

April 30th 04, 06:01 AM

Dave Martin wrote:

> Whatever happened to teaching good look out and airmanship?
>

Nothing. It's still taught and practiced as effectively, efficiently
and thoroughly as it ever was - and has been for many years. And it's
just as ineffective as it ever was.

Are you one of those who see it as simply a problem of laziness and
complacency? You're probably right but they're both endemic in human
nature and won't change now. For jobs as important as this, monitoring
systems designed with built-in tendencies to distraction and complacency
- and with multiple duties just to top it off - are simply inadequate
and always will be.

All forms of training in lookout are doomed to fail because of basic
human limitations. Not just optical limitations. Humans are simply bad
at continuous alertness and monitoring for a very low probability threat
over a long period. That's why we no longer have engineer's panels in
the flight decks of large aeroplanes. There's as much or more to
monitor than there always was - we've just accepted that humans don't do
it well and found other solutions.

Gliders have the highest rate of midairs of all forms of hard wing
aviation. I'm happy with the collision threat and the things I do to
minimise it and I'll go on flying gliders. If you're not happy, Dave,
you need to accept that it won't be improved without electronic
assistance.

Isn't 50 or more years enough?

Graeme Cant

Don Johnstone

April 30th 04, 09:03 AM

At 05:12 30 April 2004, Graeme Cant wrote:

'Gliders have the highest rate of midairs of all forms
of hard wing aviation.'

Why is that? Are glider pilots in general less capable
of keeping a good lookout? In my experience no, they
are not. It is because we put ourselves in a position
where we are more likely to come into contact with
other gliders. As a matter of course we accept the
need to fly close to one another whereas the rest of
the GA community and commercial sector try to stay
as far apart as possible. The military do deliberately
fly close to one another, is this not the reason why
military aircraft have more mid-airs with each other
than airliners have with each other?

I have to agree that gadgets are not the answer to
the problem, good lookout and situational awareness
is, and the good sense to bug out if you loose that.

Just assume for one minute that a device could do all
that has been proposed, predict a collision with another
thermalling glider. The alarm goes off and the pilot
takes immediate avoiding action, that is what the device
is for, and immediately puts himself in the path of
another glider in the thermal who did not figure in
the prediction. The cure could be worse than the disease,
such a device has the potential of causing the very
event it seeks to prevent. Remember you are never alone
in a thermal for long, if the lift is good others will
want to share it, you only have to look up at the sky
a few minutes before the gate opens at a comp when
there is only one good thermal to see what I mean.
Can you imagine the carnage if they all start to react
to collision alarms? At least at the moment they are
all doing more or less the same thing.

The answer is, good lookout, good situational awareness
and the ability to put safety first, press on itius
second. Don't expect the other guy to get out of your
way, get out of his, and if that means he has an advantage,
sobeit, at least you continue to fly on intact.

DAJ
>
>> Whatever happened to teaching good look out and airmanship?
>>
>
>Nothing. It's still taught and practiced as effectively,
>efficiently
>and thoroughly as it ever was - and has been for many
>years. And it's
>just as ineffective as it ever was.
>
>Are you one of those who see it as simply a problem
>of laziness and
>complacency? You're probably right but they're both
>endemic in human
>nature and won't change now. For jobs as important
>as this, monitoring
>systems designed with built-in tendencies to distraction
>and complacency
>- and with multiple duties just to top it off - are
>simply inadequate
>and always will be.
>
>All forms of training in lookout are doomed to fail
>because of basic
>human limitations. Not just optical limitations.
>Humans are simply bad
>at continuous alertness and monitoring for a very low
>probability threat
>over a long period. That's why we no longer have engineer's
>panels in
>the flight decks of large aeroplanes. There's as much
>or more to
>monitor than there always was - we've just accepted
>that humans don't do
>it well and found other solutions.
>
>Gliders have the highest rate of midairs of all forms
>of hard wing
>aviation. I'm happy with the collision threat and
>the things I do to
>minimise it and I'll go on flying gliders. If you're
>not happy, Dave,
>you need to accept that it won't be improved without
>electronic
>assistance.
>
>Isn't 50 or more years enough?
>
>Graeme Cant
>
>

Dave Martin

April 30th 04, 09:21 AM

At 05:12 30 April 2004, Graeme Cant wrote:
>Dave Martin wrote:
>
>> Whatever happened to teaching good look out and airmanship?
>>
>
>Nothing. It's still taught and practiced as effectively,
>efficiently and thoroughly as it ever was - and has
been for many years. And it's just as ineffective
as it ever was.
>Are you one of those who see it as simply a problem
>of laziness and complacency? You're probably right
but they're both endemic in human nature and won't
change now. For jobs as important as this, monitoring
systems designed with built-in tendencies to distraction
and complacency and with multiple duties just to top
it off - are simply inadequate
and always will be.

>All forms of training in lookout are doomed to fail
>because of basic human limitations. Not just optical
limitations. Humans are simply bad at continuous alertness
and monitoring for a very low probability threat over
a long period. That's why we no longer have engineer's
panels in the flight decks of large aeroplanes. There's
as much or more to monitor than there always was -
we've just accepted that humans don't do it well and
found other solutions.

>Gliders have the highest rate of midairs of all forms
>of hard wing aviation. I'm happy with the collision
threat and the things I do to minimise it and I'll
go on flying gliders. If you're not happy, Dave, you
need to accept that it won't be improved without electronic
assistance.

>Isn't 50 or more years enough?

>Graeme Cant

Graeme

Where did I say I wasn't happy with the present situation
?

Adding an electronic device will not ease the problem,
in the majority of cases it could compound the problems
faced by the average pilot.

Large aircraft do not fly in close proximity to others
in great numbers such as a thermal gaggle. They also
have such things as transponders, outside radar support
from control towers and other sophisticated equipment
plus the electronic power to support all the devices.
In the main they fly in regulated airspace, where everyone
has the same equipment

Flying in isolation such a device may help but in crowded
skies I suspect the information supplied would overload
the equipment and pilot, as you say above, 'Humans
are simply bad at continuous alertness and monitoring
for a very low probability threat over a long period.'

How does this equate with a large competiton gaggle
who must monitor high probability threats over long
periods say several hours and during their flight will
meet others not in their competition on their flight
path. I suppose someone will say they train for this
type of flying.

Fitting units to gliders in isolation will also give
the pilot a false sense of security.

You ask, 'Isn't 50 or more years enough?'

1 year is too long!

Dave

>

303pilot

April 30th 04, 03:53 PM

"Bill Daniels" > wrote in message
news:sofkc.273$ts3.24024@attbi_s02...
>
> "303pilot" <brentUNDERSCOREsullivanATbmcDOTcom> wrote in message
> ...
<snip>
> > >
> > This still leaves the problem I think Andy was getting at of what is the
> > acceptable false positive:false negative ratio?
> > Too many false positives and pilots won't use it.
> > False negatives would lead to collisions, deaths and, at least in the
US,
> > lawsuits that would likely put the manufacturer out of business.
> >
> > Brent
> >
> >
>
> We can't ask for perfection or nothing will ever be available. It seems
to
> me that there are two indications we should be looking for in a basic
> anti-collision device.

I'm not one to make perfection the enemy of improvement....

>
> 1, There are (n) gliders in close proximity - say 1 kilometer. Even
simple
> GPS broadcast devices should be able to determine the number of gliders
> nearby. It should beep softly when the number changes. (If the device
says
> there are 3 gliders nearby and you can only see 2, you need to keep
> looking.)

I think stopping here would be a good trade-off between improvement and
perfection. Helping me identify that there's something I don't know that I
don't know is very valuable. While we're dreaming, how about the ability to
verbally acknowledge visual contact with 2 of the 3 ships and let the
computing & display power focus on helping us find the unseen ship?

Andy Durbin

April 30th 04, 05:17 PM

"Bill Daniels" > wrote in message news:<sofkc.273>
> 2, If one of these represents a collision danger, the device should give a
> bearing. The device need only determine that the target is at or near the
> same altitude, the distance is closing and the relative bearing is nearly
> constant. If there is only 1% chance of an actual collision, that would get
> my undivided attention.

And that's the part that really scares me! It's is far to easy to
focus on a known threat to the total exclusion of searching for the
unknown threats. I've seen far too many airplane drivers place full
reliance on ATC traffic calls and more recently on TCAS advisories.
As glider pilots we face the same problem when joining thermals. It's
far too easy to narrow one's scan to all the known traffic, to plan
the entry based on that knowledge, and then to be surprised by another
glider that could have been seen with a wider scan.

Collision warning devices can increase safety if all gliders have them
and they are working. When only a few gliders are equipped there
could be a reduction in safety.

Andy

Bill Daniels

April 30th 04, 05:21 PM

"303pilot" <brentUNDERSCOREsullivanATbmcDOTcom> wrote in message
> >
> > 1, There are (n) gliders in close proximity - say 1 kilometer. Even
> simple
> > GPS broadcast devices should be able to determine the number of gliders
> > nearby. It should beep softly when the number changes. (If the device
> says
> > there are 3 gliders nearby and you can only see 2, you need to keep
> > looking.)
>
> I think stopping here would be a good trade-off between improvement and
> perfection. Helping me identify that there's something I don't know that
I
> don't know is very valuable. While we're dreaming, how about the ability
to
> verbally acknowledge visual contact with 2 of the 3 ships and let the
> computing & display power focus on helping us find the unseen ship?
>
>

Unfortunately, discrete tracking and acknowledgement will add an order of
magnitude to the computing power needed. Providing bearing and distance to
any glider that presents greater than zero probability of a collision is
pretty easy by comparison. The number of glider thus reported will be low
even in a large gaggle.

Bill Daniels

Rory O'Conor

April 30th 04, 05:48 PM

Mid Air collisions are a problem. Maybe we need to
pull together more information about them.

There are a number of different phases of flight
during which they occur:

Climbing phase (high Angle of Attack)
(power planes only)
Circuit phase (all planes)
Aerobatics (all planes)
IFR & low visibility flight (all planes)
Normal flight (all planes)
Thermalling (soaring planes only)

We need to understand the proportion of collisions
occurring in the different phases and the potential
contributory factors. Road Traffic Accidents happen
more often in good weather than bad. It is not
entirely clear that thermal collisions happen more
often in competition gaggles than when there are only
two in a thermal, whatever our instincts.

For the different flight phases, different factors
will be more or less important and the solutions and
devices to prevent collisions may be different.

Personnally I would be surprised if TCAS devices could
cope with resolving the trajectories of thermalling
gliders other than the basic level of identifying
another nearby plane. Thus I suspect that the main
detection instrument in thermals remains the eyeball.
In which case, every effort should be made to ensure
the best use of the eyeball in thermals.

There may be a role for such devices in other phases
eg normal flight and IFR.

The only power planes that regularly fly close
together are the military and aerobatic display teams.
I am sure that the Red Arrows are fitted with the
instruments that they best require, but I would be
most surprised if they have any electronic device
warning them that they are about to hit a team-mate.
I expect that they do a lot of training, have superb
lookout and excellent communications.

I would assume that a TCAS/GPS device will be making
noises at 1 mile and probably very loud noises at 1/4
mile (1500 ft). With a typical thermalling diameter
of 200-600 feet and circling period of less than 20
seconds, any normal TCAS would be screaming fit to be
turned off!

We are also entering the area where the margin of
error for a GPS (30 ft horizontally, 100 ft
vertically) is a significant issue. GPS is not
accurate enough to tell which side of the highway you
are driving on, nor probably to determine the correct
seperation of two thermalling gliders when the pilots
using their eyeballs consider that they are adequately
seperated.

I cannot envisage an electronic GPS device for
avoiding intra-thermal collisions, assuming that the
planes are going to remain in the same thermal.

Rory

Dave Martin

April 30th 04, 05:59 PM

This is what it boils down to EDUCATION/TRAINING

Training pilots how to look out.
How to concentrate,
What the dangers are, real and perceived and potential
and where these danger lurk in a particular phase of
flight.

We will never eliminate accidents but by education
we can reduce the opportunities. Train hard fly easy
as some one said!

Dave

At 17:00 30 April 2004, Rory O'Conor wrote:
>Mid Air collisions are a problem. Maybe we need to
>pull together more information about them.
>
>There are a number of different phases of flight
>during which they occur:
>
>Climbing phase (high Angle of Attack)
> (power planes only)
>Circuit phase (all planes)
>Aerobatics (all planes)
>IFR & low visibility flight (all planes)
>Normal flight (all planes)
>Thermalling (soaring planes only)
>
>We need to understand the proportion of collisions
>occurring in the different phases and the potential
>contributory factors. Road Traffic Accidents happen
>more often in good weather than bad. It is not
>entirely clear that thermal collisions happen more
>often in competition gaggles than when there are only
>two in a thermal, whatever our instincts.
>
>For the different flight phases, different factors
>will be more or less important and the solutions and
>devices to prevent collisions may be different.
>
>Personnally I would be surprised if TCAS devices could
>cope with resolving the trajectories of thermalling
>gliders other than the basic level of identifying
>another nearby plane. Thus I suspect that the main
>detection instrument in thermals remains the eyeball.
>In which case, every effort should be made to ensure
>the best use of the eyeball in thermals.
>
>There may be a role for such devices in other phases
>eg normal flight and IFR.
>
>The only power planes that regularly fly close
>together are the military and aerobatic display teams.
>I am sure that the Red Arrows are fitted with the
>instruments that they best require, but I would be
>most surprised if they have any electronic device
>warning them that they are about to hit a team-mate.
>I expect that they do a lot of training, have superb
>lookout and excellent communications.
>
>I would assume that a TCAS/GPS device will be making
>noises at 1 mile and probably very loud noises at 1/4
>mile (1500 ft). With a typical thermalling diameter
>of 200-600 feet and circling period of less than 20
>seconds, any normal TCAS would be screaming fit to
>be
>turned off!
>
>We are also entering the area where the margin of
>error for a GPS (30 ft horizontally, 100 ft
>vertically) is a significant issue. GPS is not
>accurate enough to tell which side of the highway you
>are driving on, nor probably to determine the correct
>seperation of two thermalling gliders when the pilots
>using their eyeballs consider that they are adequately
>seperated.
>
>I cannot envisage an electronic GPS device for
>avoiding intra-thermal collisions, assuming that the
>planes are going to remain in the same thermal.
>
>Rory
>
>
>
>

Bill Daniels

April 30th 04, 06:08 PM

"Andy Durbin" > wrote in message
om...
> "Bill Daniels" > wrote in message news:<sofkc.273>
> > 2, If one of these represents a collision danger, the device should give
a
> > bearing. The device need only determine that the target is at or near
the
> > same altitude, the distance is closing and the relative bearing is
nearly
> > constant. If there is only 1% chance of an actual collision, that would
get
> > my undivided attention.
>
> And that's the part that really scares me! It's is far to easy to
> focus on a known threat to the total exclusion of searching for the
> unknown threats. I've seen far too many airplane drivers place full
> reliance on ATC traffic calls and more recently on TCAS advisories.
> As glider pilots we face the same problem when joining thermals. It's
> far too easy to narrow one's scan to all the known traffic, to plan
> the entry based on that knowledge, and then to be surprised by another
> glider that could have been seen with a wider scan.
>
> Collision warning devices can increase safety if all gliders have them
> and they are working. When only a few gliders are equipped there
> could be a reduction in safety.
>
>
> Andy

So, another argument for doing nothing.

Bill Daniels

Bill Daniels

April 30th 04, 06:10 PM

"Rory O'Conor" > wrote in message
...
> Mid Air collisions are a problem. Maybe we need to
> pull together more information about them.
>
> There are a number of different phases of flight
> during which they occur:
>
> Climbing phase (high Angle of Attack)
> (power planes only)
> Circuit phase (all planes)
> Aerobatics (all planes)
> IFR & low visibility flight (all planes)
> Normal flight (all planes)
> Thermalling (soaring planes only)
>
> We need to understand the proportion of collisions
> occurring in the different phases and the potential
> contributory factors. Road Traffic Accidents happen
> more often in good weather than bad. It is not
> entirely clear that thermal collisions happen more
> often in competition gaggles than when there are only
> two in a thermal, whatever our instincts.
>
> For the different flight phases, different factors
> will be more or less important and the solutions and
> devices to prevent collisions may be different.
>
> Personnally I would be surprised if TCAS devices could
> cope with resolving the trajectories of thermalling
> gliders other than the basic level of identifying
> another nearby plane. Thus I suspect that the main
> detection instrument in thermals remains the eyeball.
> In which case, every effort should be made to ensure
> the best use of the eyeball in thermals.
>
> There may be a role for such devices in other phases
> eg normal flight and IFR.
>
> The only power planes that regularly fly close
> together are the military and aerobatic display teams.
> I am sure that the Red Arrows are fitted with the
> instruments that they best require, but I would be
> most surprised if they have any electronic device
> warning them that they are about to hit a team-mate.
> I expect that they do a lot of training, have superb
> lookout and excellent communications.
>
> I would assume that a TCAS/GPS device will be making
> noises at 1 mile and probably very loud noises at 1/4
> mile (1500 ft). With a typical thermalling diameter
> of 200-600 feet and circling period of less than 20
> seconds, any normal TCAS would be screaming fit to be
> turned off!
>
> We are also entering the area where the margin of
> error for a GPS (30 ft horizontally, 100 ft
> vertically) is a significant issue. GPS is not
> accurate enough to tell which side of the highway you
> are driving on, nor probably to determine the correct
> seperation of two thermalling gliders when the pilots
> using their eyeballs consider that they are adequately
> seperated.
>
> I cannot envisage an electronic GPS device for
> avoiding intra-thermal collisions, assuming that the
> planes are going to remain in the same thermal.
>
> Rory
>
>
And yet another....

Bill Daniels

Bill Daniels

April 30th 04, 06:14 PM

"Dave Martin" > wrote in message
...
> This is what it boils down to EDUCATION/TRAINING
>
> Training pilots how to look out.
> How to concentrate,
> What the dangers are, real and perceived and potential
> and where these danger lurk in a particular phase of
> flight.
>
> We will never eliminate accidents but by education
> we can reduce the opportunities. Train hard fly easy
> as some one said!
>
> Dave
>
> At 17:00 30 April 2004, Rory O'Conor wrote:
> >Mid Air collisions are a problem. Maybe we need to
> >pull together more information about them.
> >
> >There are a number of different phases of flight
> >during which they occur:
> >
> >Climbing phase (high Angle of Attack)
> > (power planes only)
> >Circuit phase (all planes)
> >Aerobatics (all planes)
> >IFR & low visibility flight (all planes)
> >Normal flight (all planes)
> >Thermalling (soaring planes only)
> >
> >We need to understand the proportion of collisions
> >occurring in the different phases and the potential
> >contributory factors. Road Traffic Accidents happen
> >more often in good weather than bad. It is not
> >entirely clear that thermal collisions happen more
> >often in competition gaggles than when there are only
> >two in a thermal, whatever our instincts.
> >
> >For the different flight phases, different factors
> >will be more or less important and the solutions and
> >devices to prevent collisions may be different.
> >
> >Personnally I would be surprised if TCAS devices could
> >cope with resolving the trajectories of thermalling
> >gliders other than the basic level of identifying
> >another nearby plane. Thus I suspect that the main
> >detection instrument in thermals remains the eyeball.
> >In which case, every effort should be made to ensure
> >the best use of the eyeball in thermals.
> >
> >There may be a role for such devices in other phases
> >eg normal flight and IFR.
> >
> >The only power planes that regularly fly close
> >together are the military and aerobatic display teams.
> >I am sure that the Red Arrows are fitted with the
> >instruments that they best require, but I would be
> >most surprised if they have any electronic device
> >warning them that they are about to hit a team-mate.
> >I expect that they do a lot of training, have superb
> >lookout and excellent communications.
> >
> >I would assume that a TCAS/GPS device will be making
> >noises at 1 mile and probably very loud noises at 1/4
> >mile (1500 ft). With a typical thermalling diameter
> >of 200-600 feet and circling period of less than 20
> >seconds, any normal TCAS would be screaming fit to
> >be
> >turned off!
> >
> >We are also entering the area where the margin of
> >error for a GPS (30 ft horizontally, 100 ft
> >vertically) is a significant issue. GPS is not
> >accurate enough to tell which side of the highway you
> >are driving on, nor probably to determine the correct
> >seperation of two thermalling gliders when the pilots
> >using their eyeballs consider that they are adequately
> >seperated.
> >
> >I cannot envisage an electronic GPS device for
> >avoiding intra-thermal collisions, assuming that the
> >planes are going to remain in the same thermal.
> >
> >Rory
> >
> >
> >
> >
>
We've trained and trained for 100 years and yet we still have collisions.
The 'Mark 20 eyeball' is a good tool but it isn't the total solution.
Humans just can't maintain the vigilance required. We have plenty of
evidence of that both clinical and anecdotal.

Bill Daniels

Ramy Yanetz

April 30th 04, 07:19 PM

I'm surprised people still beleive that eyes are better than
electronic equipment.
Consider the following:
1 - You don't see behind and below, and even forward visibility is
somewhat restricted, depend on cockpit style.
2 - We fly invisible aircrafts. Did you notice how quickly a sailplane
disappears when it flies away? If you stand on a runway behind a
launching glider it almost disappears before it reaches the end of the
runway, this is less than a mile!
3 - While you can notice planty of aircrafts flying nearby, the ones
on a direct collision course are the hardest to detect since they look
stationary relatively to you! I once barely noticed while thermaling a
strange stationary dot in the sky and wondered what was it, the next
turn it turned into an airliner heading directly to me and I had to
perform an evasive maneuver! Since then I am flying with a transponder
and never saw an airliner nearby again.
4 - The above gets even more difficult if not impossible to detect
when the threat is flying perpendicular to you.
5 - The main reason why we don't colide with other aircrafts more
often is simply the fact that the sky is (still) big and the chance
that 2 aircrafts will occupy the same 4 dimensions is rare.

Ramy

Dave Martin > wrote in message >...
> At 05:12 30 April 2004, Graeme Cant wrote:
> >Dave Martin wrote:
> >
> >> Whatever happened to teaching good look out and airmanship?
> >>
> >
> >Nothing. It's still taught and practiced as effectively,
> >efficiently and thoroughly as it ever was - and has
> been for many years. And it's just as ineffective
> as it ever was.
> >Are you one of those who see it as simply a problem
> >of laziness and complacency? You're probably right
> but they're both endemic in human nature and won't
> change now. For jobs as important as this, monitoring
> systems designed with built-in tendencies to distraction
> and complacency and with multiple duties just to top
> it off - are simply inadequate
> and always will be.
>
> >All forms of training in lookout are doomed to fail
> >because of basic human limitations. Not just optical
> limitations. Humans are simply bad at continuous alertness
> and monitoring for a very low probability threat over
> a long period. That's why we no longer have engineer's
> panels in the flight decks of large aeroplanes. There's
> as much or more to monitor than there always was -
> we've just accepted that humans don't do it well and
> found other solutions.
>
> >Gliders have the highest rate of midairs of all forms
> >of hard wing aviation. I'm happy with the collision
> threat and the things I do to minimise it and I'll
> go on flying gliders. If you're not happy, Dave, you
> need to accept that it won't be improved without electronic
> assistance.
>
> >Isn't 50 or more years enough?
>
> >Graeme Cant
>
> Graeme
>
> Where did I say I wasn't happy with the present situation
> ?
>
> Adding an electronic device will not ease the problem,
> in the majority of cases it could compound the problems
> faced by the average pilot.
>
> Large aircraft do not fly in close proximity to others
> in great numbers such as a thermal gaggle. They also
> have such things as transponders, outside radar support
> from control towers and other sophisticated equipment
> plus the electronic power to support all the devices.
> In the main they fly in regulated airspace, where everyone
> has the same equipment
>
> Flying in isolation such a device may help but in crowded
> skies I suspect the information supplied would overload
> the equipment and pilot, as you say above, 'Humans
> are simply bad at continuous alertness and monitoring
> for a very low probability threat over a long period.'
>
>
> How does this equate with a large competiton gaggle
> who must monitor high probability threats over long
> periods say several hours and during their flight will
> meet others not in their competition on their flight
> path. I suppose someone will say they train for this
> type of flying.
>
> Fitting units to gliders in isolation will also give
> the pilot a false sense of security.
>
> You ask, 'Isn't 50 or more years enough?'
>
> 1 year is too long!
>
> Dave
>
>
>
>
>
>
>
>
>
> >

Finbar

April 30th 04, 11:16 PM

We've tried "look out the window." We still have collisions. Since
human capabilities change only over evolutionary time, and training
programs that encourage good use of existing capabilities have been in
place for some time, we should assume that training and exhortations
have achieved as much improvement as they ever will. The remaining
collision risk must be reduced through some other means.

The traffic pattern and thermals are two high-density traffic
environments where aircraft maneuvering renders collision prediction
difficult. It's not just difficult for machines, it's also difficult
for pilots. During pilot training the task must be taught in several
steps: 1) be aware of how many other aircraft are nearby 2) locate
them 3) avoid getting close to those aircraft unless necessary 4) if
proximity is necessary, watch (i.e., try to predict) the path of the
other aircraft and avoid going toward the place where it is going 5)
learn to anticipate possible unpredictable variations in the path of
the other aircraft also and avoid going toward those areas. Level 5)
is probably only required in thermals and in formation flying. When
we begin thermaling, most of us have to use 3) because we're not good
enough at 4) or 5).

However, at the moment pilots are much better than machines at 4) and
5), while machines are much better than pilots at 1) and 2). Yet, if
1) fails, the rest is useless.

The fact that machines can't do the whole job does NOT mean they can't
be helpful. A machine that could inform a pilot that there are 5
other aircraft in the thermal within +/- 500 ft would be valuable to a
very alert contest pilot who could account for only 4 of them. The
tasks of finding the 5th, and avoiding all 5, might still have to rely
on the Mark I Eyeball.

Of course, pilots in gaggles know that they are in a high
collision-risk situation, and they devote significant attention to
seeing and avoiding other aircraft. Pilots who think they are alone
in the sky devote much less mental capacity to those tasks. Insisting
on "always" maintaining lookout vigilance is ill-advised: many of us
have a pretty high cognitive load a high percentage of the time in
flight, and if we devote too much attention to lookout we may well
lose navigational or meteorological situational awareness, or even
just tire ourselves out mentally, leaving ourselves vulnerable when
attention is important later. This is where a machine could help, by
maintaining a scan and verifying that, indeed, the collision risk is
low. If that changes, the machine can alert the pilot, allowing the
pilot to properly switch mental capacity to "see and avoid." In fact,
this is the primary benefit of flight following during powered VFR
flight, and it's no small benefit.

Insisting that a technology is useless unless it can solve the whole
problem makes perfection the enemy of the good. It's also, in this
case, blind to the imperfection of the current technology - the Mark I
Eyeball - which plenty of science has shown is, in most near-miss
scenarios, far less valuable than the sheer size of the sky.

Mike Borgelt

May 1st 04, 12:00 AM

On 30 Apr 2004 15:16:05 -0700, (Finbar) wrote:

>We've tried "look out the window." We still have collisions. Since
>human capabilities change only over evolutionary time, and training
>programs that encourage good use of existing capabilities have been in
>place for some time, we should assume that training and exhortations
>have achieved as much improvement as they ever will. The remaining
>collision risk must be reduced through some other means.
efl
>
>Insisting that a technology is useless unless it can solve the whole
>problem makes perfection the enemy of the good. It's also, in this
>case, blind to the imperfection of the current technology - the Mark I
>Eyeball - which plenty of science has shown is, in most near-miss
>scenarios, far less valuable than the sheer size of the sky.

Finbar, I think that post sums it up nicely. The Swiss FLARM would
appear to be a good start.

Having something say " traffic, 5 miles. closing, level" would give
you something to look for and would essentially be an automated and
autonomous flight following service.

Unfortunately we won't get sensible ADS-B anytime soon at any
reasonable price for the rest of aviation. Take a look at the system
specifications and you'll soon see it is over specified by about 3
orders of magnitude. Politics again.

A simple GPS/VHF based system was demonstrated in Australia a few
years ago but the authorities didn't follow through because there were
no ICAO standards for such a system. Even now ADS-B looks like
operating on different frequencies in different countries.

Mike Borgelt

Finbar

May 1st 04, 06:49 AM

Mike,

The FLARM concept has been painfully obvious, from a technology point
of view, since the introduction of low-cost GPS. In fact, it could
even have been partially implemented with LORAN, but those receivers
were expensive and were never widely deployed.

Unfortunately, FLARM-type collision avoidance is only going to work if
it's deployed to virtually all aircraft, which would require the
authorities to insist on it. This won't happen: ADS-B is the chosen
approach.

It seems to me that TIS-B is most likely what will first begin to
provide us with the functionality we need - and actually get deployed.
TIS-B (Traffic Information Service - Broadcast) is a portion of
ADS-B, essentially a broadcast of the radar returns seen by ATC. At
the moment it has limited coverage in the US but you can receive it -
however you need to spend about $15,000 on avionics including a Mode S
transponder plus a display unit designed for bigger panels than we
have. Still, no doubt it will soon occur to some entrepreneur that a
TIS-B receiver without all the Mode S baggage, designed for display on
a PDA might well find a market (lots of Cezzna drivers think $15k is a
lot of money too).

Eric Greenwell

May 1st 04, 07:07 AM

Don Johnstone wrote:

> The answer is, good lookout, good situational awareness
> and the ability to put safety first, press on itius
> second.

This doesn't sound like an answer to me. I do all those things, yet I've
still come close to collisions.

> Don't expect the other guy to get out of your
> way, get out of his, and if that means he has an advantage,
> sobeit, at least you continue to fly on intact.

I don't expect the other guy to get out of my way, but I've still come
close to collisions.

These have generally been contest situations involving many gliders, but
not always. An effective, but not perfect, way to avoid collsions is to
always fly well away from other gliders. It's not a perfect way, because
you can't stop other glider from seeing you and joining you.

I'm surprised people are willing to claim a technological solution is
unworkable without any demonstration of it's ability. How can you say
"The answer is, good lookout, good situational awareness and the ability
to put safety first, press on itius second", when you have no data on
the proposed solution? Wouldn't a better remark be "Try it, and show us
the results?"

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

OscarCVox

May 1st 04, 10:00 AM

In a recent mid air in the UK it was a quiet day, bright and hazy with poor
visability. There were only 3 or 4 aircraft in the air at the same time.
Percieved low risk of collision so level of lookout was low?
A very experienced (10,000+ hrs in gliders) was killed.

Dave Martin

May 1st 04, 11:41 AM

Anti-collision warnings
Once again a thread on RAS has polarised neatly into
two camps

Argument 1.

The mark 1 eyeball and the USB (Universal Standard
Brain) are the best!

Train them and the problem is solved.

Argument 2

Statistics show the above equipment is outdated for
present needs it needs replacing or providing with
some assistance.

OK.

Accept that at present theory 1 is the best we have
come up with so far and that change is needed.

The challenge is now how to assist the brain solve
the problem. Individuals are not the probelm, it is
everyone else out there who is trying to get you. Remember
it is the aircraft you do not see that gets you!

So all we need is a simple instrument that meets the
following criteria.

1. It will detect at least 40 gliders in close proximity.
2. Plus those within a 5 nautical mile range.
3. Work out their relative positions.
4. Assess the collision threat of each and every one.
5. Feed the information to the pilot of each glider
in a readable format that can be assessed within the
bat of an eyelid.
6. Develop the instrument with little financial assistance
from within the movement.
7. Ensure every glider has the equipment fitted.
8. Ensure the equipment works with very little power
consumption.
9. Ensure that the cost is no more that a launch fee.
10. Make fitting compulsary to ALL aircraft flying
in uncontrolled airspace.

No one who fits any form of instrument to his glider
can be accused of being anti progress. BUT until the
above problems are more than half solved the practicalities
of a succesfull anti collision device are low.

In he mean time I return to argument 1. At present
this is the best we have!

If technology comes up with a reliable assistant this
must be good until then WE MUST ensure that our pilots
are trained on the dangers that lurk out there.

Dave

W.J. $Bill$ Dean $U.K.$.

May 1st 04, 12:49 PM

Who are you, OscarCVox? Why the nickname?

Where do you fly?

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.
Talgarth, Nympsfield, Mynd, formerly Lasham for over 20 years.

>
> "OscarCVox" > wrote in message
> ...
>
> In a recent mid air in the UK it was a quiet day, bright and hazy with
> poor visibility.
> There were only 3 or 4 aircraft in the air at the same time.
> Perceived low risk of collision so level of lookout was low?
> A very experienced (10,000+ hrs in gliders) was killed.
>

Bill Daniels

May 1st 04, 03:04 PM

"Dave Martin" > wrote in message
...

> So all we need is a simple instrument that meets the
> following criteria.
>
> 1. It will detect at least 40 gliders in close proximity.
> 2. Plus those within a 5 nautical mile range.
> 3. Work out their relative positions.
> 4. Assess the collision threat of each and every one.
> 5. Feed the information to the pilot of each glider
> in a readable format that can be assessed within the
> bat of an eyelid.
> 6. Develop the instrument with little financial assistance
> from within the movement.
> 7. Ensure every glider has the equipment fitted.
> 8. Ensure the equipment works with very little power
> consumption.
> 9. Ensure that the cost is no more that a launch fee.
> 10. Make fitting compulsary to ALL aircraft flying
> in uncontrolled airspace.
>

The above vastly overstates the issue. It's yet one more "do nothing"
argument. Make the problem seem too difficult and people will give up.

Listing the nearby gliders is very easy. You don't need to list them by
contest ID just the number within a reasonable distance. Those beyond 1 Km
are of little interest. You aren't interested in the relative positions of
all gliders, only those that represent a non-zero probably of a collision.
At any instant, out of 40 gliders, only one or two might represent a real
hazard.

This is a very easy bit of computer programming. Devices that do almost
exactly this are already available as consumer devices. (FRS walkie talkies
with integral GPS ~ $150US) Only small improvements are needed for glider
use.

Making every glider carry one is not likely or necessary but it could become
a requirement for contest flying. Clubs with a large fleet might decide to
install them. Most gliders fly within a local area so local rules will
work.

This device need only work with gliders. The rest of the aircraft fleet
will use transponders. For protection from these, you need a transponder
too.

Bill Daniels

Jeff Dorwart

May 1st 04, 05:48 PM

Argument number 3.While collision avoidance equipment is available and
expensive (not because of politics really but because
of liability), it is not flawless. I have spent thousands
of hours with TCAS and have seen numerous near mid-air
reports filed. It is a vast improvement to nothing.
It does not replace the mark I eyball, but augments
it enhancing safety. Many pilots get balled up (preoccupied)
looking for the reported TCAS traffic and fail to see
the piper cub buzzing by till he passes 300 ft. over
the cockpit. Good tool. Not fallible, distracting
and expensive. I had one installed on a Gulfstream
1 for $35000.00 and the equipment requirement is the
same for a C-172. An alternative, which is listed
on Tim's W&W web site is a radio monitor that receives
the IFF transponder (which the TCAS also is) and gives
a range and relative altitude for the closest target.
Not a bad tool for cruising solo but not useful in
a thermal of more than two where of course (hmm...)you
would know the proximity of that one other target.
Multiple targets that are transponder equipped within
the minimum range of .1mi (600 ft) displayed would
not be displayed. Like I said a good tool for on the
run, not in a thermal.Now to the meat of the matter. The most valuable lesson
we can learn from the recent mid airs we have suffered
is improved Communications. Virtually all gliders
are radio equipped. In the pattern with very diverse
aircraft types we avoid collisions not only with visual
diligence, but mostly by communicating clearly where
we are flying. If you are entering a thermal, announce
to those in the vicinity of your intentions. I am
not suggesting constant radio communications while
thermalling, but if you are joining say so. If you
tell your neighbors you intend to do something and
you decide to do something else, say so.I am not suggesting that technology does not exist
or can be developed to combat this, nor do I think
we should sit on our laurels waiting for someone else
to come up with some magic tool to do it for us. I
think we should press on talking about possibilities
and put our briains together to come up with that tool.
Possibly those of the technology camp can start an
LLC to mitigate the liability and develop a tool but
I think we are obligated to improve the tools we already
have to increase our situational awareness. That tool
is the radio and the improvement we can make today
is to practice good communications of our intentions.v/rjeff

Michel Talon

May 1st 04, 07:20 PM

Jeff Dorwart > wrote:
>

Let me mention an important factor here, the age of the pilot.
I have constated on myself that as one ages, the field of vision
becomes narrower, not to mention that attention is not of the same
quality, reflexes become poor, etc. This could well be one of the most
important factors at play here. Sooaring is much much bettre fitted to
young people in excellent health and doing a lot of sports (i mean
sports like squash) than to old people.

>

--

Michel TALON

Don Johnstone

May 1st 04, 08:05 PM

I don't think that collisions between gliders is a
matter of pure eyesight, it is more situational awareness
and expectation. There is also a school of thought
that says that an experienced pilot uses his experience
not to get into situations where quick reflexes are
involved. I am not sure that flying is an area where
reflex actions are necessarily a good thing.

Young bull to old bull 'Lets run down the paddock and
service some of those cows'
Old bull to young bull, 'Lets walk down and service
all of them'

At 18:36 01 May 2004, Michel Talon wrote:
>Jeff Dorwart wrote:
>>
>
>Let me mention an important factor here, the age of
>the pilot.
>I have constated on myself that as one ages, the field
>of vision
>becomes narrower, not to mention that attention is
>not of the same
>quality, reflexes become poor, etc. This could well
>be one of the most
>important factors at play here. Sooaring is much much
>bettre fitted to
>young people in excellent health and doing a lot of
>sports (i mean
>sports like squash) than to old people.
>
>
>>
>
>--
>
>Michel TALON
>
>

Don Johnstone

May 1st 04, 08:28 PM

I am not against a technology solution per se. What
I am against is looking for a solution which could
take years to implement when a solution is needed tomorrow.

It seems to me that several people think that the introduction
of technology will be simple, it won't. The problem
is extremely complex. Assuming that GPS is accurate
enough, it isn't (especially in vertical positioning),
and that it updates qickly enough, it doesn't, at least
the ones we use at the moment don't, that still leaves
the problem of keeping track of 40 gliders constantly
changing direction realtime, can AWACS do that? Still
leaves the problem of how you keep the pilot informed,
display in the cockpit? I don't think so. Having sorted
out all that, what does a pilot do in response to an
urgent warning of collision, turn into another glider
which was not logged as a threat until the sudden evasive
turn was made. Technology might give the warning but
it is the human that has to react.

I personally don't think we have the technology or
expertise to design such a system or indeed the expertise
to put it in a small enough space to fit in a glider
right now, and the cost could be more than the average
glider is worth. I am not saying do nothing, what I
am saying is do something realistic and achievable
now. I have little doubt that what has been proposed
will be with us in 10 years time but it is now that
we have a problem.

I stand by what I originally wrote, humans are the
cause of accidents, humans can prevent accidents. Whether
we have the will to do it is another matter entirely.

If GPS was that accurate radar whould be obsolete and
transponders museum items.

At 06:18 01 May 2004, Eric Greenwell wrote:
>
>
>Don Johnstone wrote:
>
>> The answer is, good lookout, good situational awareness
>> and the ability to put safety first, press on itius
>> second.
>
>This doesn't sound like an answer to me. I do all those
>things, yet I've
>still come close to collisions.
>
>> Don't expect the other guy to get out of your
>> way, get out of his, and if that means he has an advantage,
>> sobeit, at least you continue to fly on intact.
>
>I don't expect the other guy to get out of my way,
>but I've still come
>close to collisions.
>
>These have generally been contest situations involving
>many gliders, but
>not always. An effective, but not perfect, way to avoid
>collsions is to
>always fly well away from other gliders. It's not a
>perfect way, because
>you can't stop other glider from seeing you and joining
>you.
>
>I'm surprised people are willing to claim a technological
>solution is
>unworkable without any demonstration of it's ability.
>How can you say
>'The answer is, good lookout, good situational awareness
>and the ability
>to put safety first, press on itius second', when you
>have no data on
>the proposed solution? Wouldn't a better remark be
>'Try it, and show us
>the results?'
>
>--
>Change 'netto' to 'net' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
>

Philip Plane

May 1st 04, 09:40 PM

The whole anti collision warning thing is way to dangerous. If you
could design and build such a device, how do you get that information
to the pilot?

At a club nearby there was a mid-air a few years ago. nobody was
hurt, but every-one was shaken up. A short while later the club
two seater was in circuit and called downwind with the wrong callsign.
The club duty pilot on the ground saw the glider in circuit and heard
the call. Noticing the difference he called the glider and warned him
that another glider was in circuit. The pilot was so concerned with
looking out for the 'other' glider that he neglected his circuit
and landed short of the airfield damaging the glider.

To busy looking for the 'other' glider to fly his own. Imagine flying
in a busy part of the sky with all that information about the other
five glider being thrust at you all the time. Distraction could cause
more problems than the information fixes.

But if collisions happen because situational awareness is inadequate,
perhaps the first step is to enhance situational awareness. A device
that could show the location of nearby gliders would be handy, but
the simpler the better. A little information that can be absorbed
in a glance and integrated into your normal scan would be useful
with being such a distraction that it was dangerous. The MK1 eyeball
may not be adequate by itself, but it is an essential tool that
we need to keep using for outside scan, not peering at some instrument.
This is especially true if there are other gliders close by.

--
Philip Plane _____
|
---------------( )---------------
Glider pilots have no visible means of support

Dave Martin

May 1st 04, 09:46 PM

At 14:18 01 May 2004, Bill Daniels wrote:
>
>'Dave Martin' wrote in message
...
>
>> So all we need is a simple instrument that meets the
>> following criteria.
>>
>> 1. It will detect at least 40 gliders in close proximity.
>> 2. Plus those within a 5 nautical mile range.
>> 3. Work out their relative positions.
>> 4. Assess the collision threat of each and every one.
>> 5. Feed the information to the pilot of each glider
>> in a readable format that can be assessed within the
>> bat of an eyelid.
>> 6. Develop the instrument with little financial assistance
>> from within the movement.
>> 7. Ensure every glider has the equipment fitted.
>> 8. Ensure the equipment works with very little power
>> consumption.
>> 9. Ensure that the cost is no more that a launch fee.
>> 10. Make fitting compulsary to ALL aircraft flying
>> in uncontrolled airspace.
>>
>
>The above vastly overstates the issue. It's yet one
>more 'do nothing'
>argument. Make the problem seem too difficult and
>people will give up.
>
>Listing the nearby gliders is very easy. You don't
>need to list them by
>contest ID just the number within a reasonable distance.
> Those beyond 1 Km
>are of little interest. You aren't interested in the
>relative positions of
>all gliders, only those that represent a non-zero probably
>of a collision.
>At any instant, out of 40 gliders, only one or two
>might represent a real
>hazard.
>
>This is a very easy bit of computer programming. Devices
>that do almost
>exactly this are already available as consumer devices.
> (FRS walkie talkies
>with integral GPS ~ $150US) Only small improvements
>are needed for glider
>use.
>
>Making every glider carry one is not likely or necessary
>but it could become
>a requirement for contest flying. Clubs with a large
>fleet might decide to
>install them. Most gliders fly within a local area
>so local rules will
>work.
>
>This device need only work with gliders. The rest
>of the aircraft fleet
>will use transponders. For protection from these,
>you need a transponder
>too.
>
>Bill Daniels
>
Bill

You are clearly a pilot in the US, with vast open skies
in which to fly.

Here in the UK our skies are crowded, we are being
squeezed by commercial ventures who need more and more
airspace
Frequently contests fly over and around other gliding
sites, pilots on cross countries select other gliding
as turn points. Local soaring is some areas can take
in can take in 10 or more other sites, plus powered
strips.

You say in addition to the anticollision device we
should also have a transponder and in the UK few glider
pilots have radio licences so they can use the ttansponder
(although this is changing). At present we do not have
the power to drive them.

At a meeting of with airtraffic controlers they were
alarmed at the thought of 40 gliders all flying in
a contest fitted with transponders, they thought it
would screw up A their computers and B their controllers
trying to make sense of 40 gliders in a thermal.

You say my argument vastly overstates the issue, I
think it is very much understated for UK flying.

These are real issues when flying cross country in
a crowded little island.

I would welcome and applaud someone who can solve the
problem but in the short term let us be realistic.

Unless everyone carries the equipment it is about as
much good as a one legged man in a butt kicking contest.
It may tell you were some gliders are but not every
one, therein lies the danger.

Enough said,

Dave

Eric Greenwell

May 2nd 04, 12:20 AM

Don Johnstone wrote:

> I am not against a technology solution per se. What
> I am against is looking for a solution which could
> take years to implement when a solution is needed tomorrow.

I'm listening for that solution, but so far all I hear is more of what
we are already doing: better training and pilots that don't make
mistakes. Propose something (I don't have any good ideas).

>
> It seems to me that several people think that the introduction
> of technology will be simple, it won't. The problem
> is extremely complex.

Ony if you think the problem is 40 gliders instead of 3 or 4, which is
all that was involved in the recent collisions.

Assuming that GPS is accurate
> enough, it isn't (especially in vertical positioning),

When I overlay the GPS altitude traces from the last flight with my two
GPS recorders, I see the greatest deviations (one trace compared to the
other) are less than +/- 50 feet. This is less than the wingspan of my
glider! Most of the time it is less than +/- 15 feet. I think this is
good enough for gliders.

> and that it updates qickly enough, it doesn't, at least
> the ones we use at the moment don't,

How much more often than once a second is required? That is 25 points
per circle, which seems like plenty to me. Our speeds and accelerations
are low, so I think an even slower rate would be adequate for
thermalling and beating back and forth on a ridge.

> that still leaves
> the problem of keeping track of 40 gliders constantly
> changing direction realtime, can AWACS do that?

Have you ever flown in a thermal with even 10 gliders? I have many
times. I can not keep track of even 10 gliders, but I can still thermal
safely when there are that many and more. We are not flying around at
random, but circling in an orderly fashion. Only the nearby gliders are
a threat that must be monitored. In any case, a system that deals with
only a few gliders will cover most of the situations.

Still
> leaves the problem of how you keep the pilot informed,
> display in the cockpit? I don't think so. Having sorted
> out all that, what does a pilot do in response to an
> urgent warning of collision, turn into another glider
> which was not logged as a threat until the sudden evasive
> turn was made. Technology might give the warning but
> it is the human that has to react.

These are not new questions, so you can be assured that people
contemplating these systems are considering them. Systems do not spring
fully featured and perfect from the mind of an engineer, but proceed
through stages of development and testing. Exactly what problems and
benefits will appear during this process can't be predicted very well.

>
> I personally don't think we have the technology or
> expertise to design such a system or indeed the expertise
> to put it in a small enough space to fit in a glider
> right now, and the cost could be more than the average
> glider is worth. I am not saying do nothing, what I
> am saying is do something realistic and achievable
> now. I have little doubt that what has been proposed
> will be with us in 10 years time but it is now that
> we have a problem.
>
> I stand by what I originally wrote, humans are the
> cause of accidents, humans can prevent accidents. Whether
> we have the will to do it is another matter entirely.

What must we do? Propose something - we're listening.

>
> If GPS was that accurate radar whould be obsolete

GPS _IS_ far more accurate than radar! But the system that uses it is
being deployed very slowly.

and
> transponders museum items.

Some of us already believe that! But I still installed one, because that
is the current system best suited to keep me and airliners separated (it
can also help keep smaller airplanes and even skydivers away from me).

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Bill Daniels

May 2nd 04, 01:19 AM

"Dave Martin" > wrote in message
...
> At 14:18 01 May 2004, Bill Daniels wrote:
> >
> >'Dave Martin' wrote in message
> ...
> >
> >> So all we need is a simple instrument that meets the
> >> following criteria.
> >>
> >> 1. It will detect at least 40 gliders in close proximity.
> >> 2. Plus those within a 5 nautical mile range.
> >> 3. Work out their relative positions.
> >> 4. Assess the collision threat of each and every one.
> >> 5. Feed the information to the pilot of each glider
> >> in a readable format that can be assessed within the
> >> bat of an eyelid.
> >> 6. Develop the instrument with little financial assistance
> >> from within the movement.
> >> 7. Ensure every glider has the equipment fitted.
> >> 8. Ensure the equipment works with very little power
> >> consumption.
> >> 9. Ensure that the cost is no more that a launch fee.
> >> 10. Make fitting compulsary to ALL aircraft flying
> >> in uncontrolled airspace.
> >>
> >
> >The above vastly overstates the issue. It's yet one
> >more 'do nothing'
> >argument. Make the problem seem too difficult and
> >people will give up.
> >
> >Listing the nearby gliders is very easy. You don't
> >need to list them by
> >contest ID just the number within a reasonable distance.
> > Those beyond 1 Km
> >are of little interest. You aren't interested in the
> >relative positions of
> >all gliders, only those that represent a non-zero probably
> >of a collision.
> >At any instant, out of 40 gliders, only one or two
> >might represent a real
> >hazard.
> >
> >This is a very easy bit of computer programming. Devices
> >that do almost
> >exactly this are already available as consumer devices.
> > (FRS walkie talkies
> >with integral GPS ~ $150US) Only small improvements
> >are needed for glider
> >use.
> >
> >Making every glider carry one is not likely or necessary
> >but it could become
> >a requirement for contest flying. Clubs with a large
> >fleet might decide to
> >install them. Most gliders fly within a local area
> >so local rules will
> >work.
> >
> >This device need only work with gliders. The rest
> >of the aircraft fleet
> >will use transponders. For protection from these,
> >you need a transponder
> >too.
> >
> >Bill Daniels
> >
> Bill
>
> You are clearly a pilot in the US, with vast open skies
> in which to fly.
>
> Here in the UK our skies are crowded, we are being
> squeezed by commercial ventures who need more and more
> airspace
> Frequently contests fly over and around other gliding
> sites, pilots on cross countries select other gliding
> as turn points. Local soaring is some areas can take
> in can take in 10 or more other sites, plus powered
> strips.
>
> You say in addition to the anticollision device we
> should also have a transponder and in the UK few glider
> pilots have radio licences so they can use the ttansponder
> (although this is changing). At present we do not have
> the power to drive them.
>
> At a meeting of with airtraffic controlers they were
> alarmed at the thought of 40 gliders all flying in
> a contest fitted with transponders, they thought it
> would screw up A their computers and B their controllers
> trying to make sense of 40 gliders in a thermal.
>
> You say my argument vastly overstates the issue, I
> think it is very much understated for UK flying.
>
> These are real issues when flying cross country in
> a crowded little island.
>
> I would welcome and applaud someone who can solve the
> problem but in the short term let us be realistic.
>
>
> Unless everyone carries the equipment it is about as
> much good as a one legged man in a butt kicking contest.
> It may tell you were some gliders are but not every
> one, therein lies the danger.
>
> Enough said,
>
> Dave
>
Yes I do fly in the vast empty skies of the western USA, thank goodness.
However, I'm also a pilot who has survived a mid-air with another glider
while flying in those "empty" skies.

Try to picture this. The little device goes "Beep" and when you look at it,
the 20mm 2-digit LED display says "06" meaning 6 gliders are within one
kilometer. My reaction is to look outside like crazy until I can see all
six. It beeps again and displays 07 meaning that another glider has joined
the gaggle. I look even harder. This uses the "Mark 1 eyeball" to it's
maximum.

Extremely accurate GPS data has nothing to do with this. If the error is
that the 7th glider is really 1.005 Km away instead of 1.000 why would I
care? If a glider joins the gaggle without this device there is a very good
chance I will see him while looking for the others even though the device
does not detect him.

It is not necessary to compute the trajectories of all gliders in the gaggle
to determine those with a collision probability. Those 500 feet above and
below present no danger whatsoever.

Now picture an advanced version. The device still displays "07" but it now
sounds "deedle, deedle, deedle" and an LED at 8 O'clock illuminates meaning
that there is a non-zero probability collision threat at that relative
bearing. The "Mark 1 eyeballs" leap into action and I look over my left
shoulder to see that the other glider will pass clear. Is this a "false
alarm"? Not really. I really wanted to see him if he was that close. I
appreciated the "heads up". The device need only compute probabilities for
those targets near and closing while near the same altitude.

Perhaps the problem is calling this an "Anti-Collision Device" when it is
really a situational awareness aid.

As for battery life, perhaps you noticed the news that a fully IFR equipped
Kestral 17 flown by Gordon Boettger flew 1562 Kilometers in 11:15 from
Minden, Nevada, USA to Steamboat Springs, Colorado. Most of the flight was
in wave above 20,000 feet. Gordon's Kestral was transponder equipped as
well as carrying a lot of other electronics to operate legally in positive
control airspace. Battery capacity didn't seem to be a problem.

The device I'm talking about would weigh less than 200 gms and run on four
AA batteries for 50+ hours. The amount of time spent looking at it will be
fractions of a second and then only when critical information is displayed.

Bill Daniels

Mark James Boyd

May 2nd 04, 01:42 AM

In article >,
>Mike,
>
>The FLARM concept has been painfully obvious, from a technology point
>of view, since the introduction of low-cost GPS. In fact, it could
>even have been partially implemented with LORAN, but those receivers
>were expensive and were never widely deployed.
>
>Unfortunately, FLARM-type collision avoidance is only going to work if
>it's deployed to virtually all aircraft, which would require the
>authorities to insist on it. This won't happen: ADS-B is the chosen
>approach.

Sort of important to this approach is "is it worth it?" and
"does the solution cause more death than the problem?"

Kind of like parachutes. If the added weight increases the
marginal stall speed to the point it causes .001% more
fatal accidents, but only saves .0092% more pilots
in breakups, then it was a bad idea. Of course it's
extremely unlikely anyone can prove the extra 15 pounds was
the cause of fatality, right?

How many added fatalities will there be because the pilot
is distracted by the bleepy noise, even though the aircraft
would have missed by six inches if neither pilot was aware?
How many will die because of the distraction itself?

This is just too hard to calculate. Huge numbers (hours
of flight)multiplied by tiny estimated numbers (risk of midair)
makes for a tough comparison. Now instead of risk
use cost in $$$$s to implement, and the true cost vs. benefit is
very difficult to estimate correctly...

--

------------+
Mark Boyd
Avenal, California, USA

Chris Rollings

May 2nd 04, 08:12 AM

Over the last 15 years or so our instrument panels
have become much more interesting, displaying vastly
more information than previously. During the same
period there has been a significant increase in the
number of pilots with the skill (and willingness) to
soar very close to other sailplanes.

The accidents are caused by our willingness to fly
in a close proximity to other gliders, that produces
the level of risk that produces the accidents we have.

A gadget that worked, if such were possible, would
probably have us all flying closer and closer together
until we got back up to the same (maximum acceptable)
perceived level of risk.

At 23:54 01 May 2004, Mark James Boyd wrote:
>In article ,
>>Mike,
>>
>>The FLARM concept has been painfully obvious, from
>>a technology point
>>of view, since the introduction of low-cost GPS. In
>>fact, it could
>>even have been partially implemented with LORAN, but
>>those receivers
>>were expensive and were never widely deployed.
>>
>>Unfortunately, FLARM-type collision avoidance is only
>>going to work if
>>it's deployed to virtually all aircraft, which would
>>require the
>>authorities to insist on it. This won't happen: ADS-B
>>is the chosen
>>approach.
>
>Sort of important to this approach is 'is it worth
>it?' and
>'does the solution cause more death than the problem?'
>
>Kind of like parachutes. If the added weight increases
>the
>marginal stall speed to the point it causes .001% more
>fatal accidents, but only saves .0092% more pilots
>in breakups, then it was a bad idea. Of course it's
>extremely unlikely anyone can prove the extra 15 pounds
>was
>the cause of fatality, right?
>
>How many added fatalities will there be because the
>pilot
>is distracted by the bleepy noise, even though the
>aircraft
>would have missed by six inches if neither pilot was
>aware?
>How many will die because of the distraction itself?
>
>This is just too hard to calculate. Huge numbers (hours
>of flight)multiplied by tiny estimated numbers (risk
>of midair)
>makes for a tough comparison. Now instead of risk
>use cost in $$$$s to implement, and the true cost vs.
>benefit is
>very difficult to estimate correctly...
>
>--
>
>------------+
>Mark Boyd
>Avenal, California, USA
>

Gerhard Wesp

May 2nd 04, 12:17 PM

Andy Durbin > wrote:
> trajectory of each aircraft, but also predict collisions based on all
> possible future trajectories for the next say 30 seconds. Try

Say 15 seconds, rather. I think it's useless to predict what will
happen in 30 seconds. Even if concentration is not at its maximum for a
moment, 15 seconds should be more than sufficient to avoid a collision
IF YOU SEE THE OTHER A/C.

> resolving that mess when there are 30+ gliders at the top of the same
> thermal waiting for a contest start. The false alarm rate would be
> unacceptable.

I don't think so. I was at the ``kickoff-meeting'' of FLARM at the ETH
Zuerich, and I can assure you that the developers are very well aware of
this problem and have adressed it. There are algorithms which perform
well in that kind of situation and given that the workload is divided
among all 30+ FLARMs CPU performance is expected to be sufficient. The
developers cited extensive simulations which they did with IGC traces
and it seems that the ``false alarm'' rate was low.

That said, of course I can at the moment only cite and trust the
developers, and a system like FLARM needs to prove itself in practice.
There are too many factors which influence collision probability that
I'd dare a prediction here. But it's an interesting concept and if the
technical/regulatory question marks can be cleared up, we'll soon have
some data on whether it can help reducing accident rates or not.

Kind regards,
-Gerhard
--
Gerhard Wesp o o Tel.: +41 (0) 43 5347636
Bachtobelstrasse 56 | http://www.cosy.sbg.ac.at/~gwesp/
CH-8045 Zuerich \_/ See homepage for email address!

Eric Greenwell

May 2nd 04, 06:18 PM

Chris Rollings wrote:
> Over the last 15 years or so our instrument panels
> have become much more interesting, displaying vastly
> more information than previously. During the same
> period there has been a significant increase in the
> number of pilots with the skill (and willingness) to
> soar very close to other sailplanes.
>
> The accidents are caused by our willingness to fly
> in a close proximity to other gliders, that produces
> the level of risk that produces the accidents we have.
>
> A gadget that worked, if such were possible, would
> probably have us all flying closer and closer together
> until we got back up to the same (maximum acceptable)
> perceived level of risk.

What situations are you thinking of where this would be true?

I don't think it would be true for thermalling together, especially in
contests, as I believe we already fly as close as practical. Flying
closer would make it too hard to maintain safe separation (because of
turbulence, the need to maneuver some, and the inability to hold a
perfect circle), even with a warning device. Possibly, we would even fly
farther apart to reduce the number of alarms (this would likely depend
on the precise behavior of the unit), or because we would realize we
were not as safe as we thought. I believe this requires flight testing
to determine.

Perhaps it would be true for ridge soaring together, but again, maybe
the alarms would actually cause us to maintain greater distance.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Don Johnstone

May 2nd 04, 07:45 PM

At 11:30 02 May 2004, Gerhard Wesp wrote:

>Say 15 seconds, rather. I think it's useless to predict
>what will
>happen in 30 seconds.

something capable of predicting what a human being
WILL do next whatever the time scale. Now that would
be something.

303pilot

May 3rd 04, 07:08 PM

"Eric Greenwell" > wrote in message
...
> Don Johnstone wrote:
> >
> > It seems to me that several people think that the introduction
> > of technology will be simple, it won't. The problem
> > is extremely complex.
>
> Ony if you think the problem is 40 gliders instead of 3 or 4, which is
> all that was involved in the recent collisions.
>
I'm not a programmer, but I work with them on a daily basis. It seems to me
that even a 3 or 4 glider problem is highly complex because sailplanes fly
in highly irregular paths. We don't even fly straight point to point--we
weave left and right, we dolphin. A ship might be going (more or less)
straight and a couple hundred feet below me. Not a threat, right? Maybe,
maybe not--what if I'm in a thermal and he's seen me and plans to join me.
He suddenly converts speed to altitude and he's in my blind spot. My GPS
has a 4 second polling cycle. Ooops.
What if two ships are in a thermal but maintaining separation. Everything's
fine, right? Sure, until we get to the top of the lift band and he suddenly
tightens his turn to go through the core as he heads out on course.

>
> Have you ever flown in a thermal with even 10 gliders? I have many
> times. I can not keep track of even 10 gliders, but I can still thermal
> safely when there are that many and more. We are not flying around at
> random, but circling in an orderly fashion. Only the nearby gliders are
> a threat that must be monitored. In any case, a system that deals with
> only a few gliders will cover most of the situations.
Orderly? To you and I yes. To a program? Not really.
Think about what happens at cloudbase in a contest gaggle. The (mostly)
orderly and similar actions (mostly same speed & bank angle) get more
random. Some pilots increase their radius purposefully suboptimizing climb
rates, others deploy a bit of spoiler, others leave. How are these actions
to be predicted?
Even if I have a 1 second polling rate on my GPS & "traffic
analysis/collision avoidance system", how many variables can change in that
one second and how fast can my safe separation be erased?

>
> Still
> > leaves the problem of how you keep the pilot informed,
> > display in the cockpit? I don't think so. Having sorted
> > out all that, what does a pilot do in response to an
> > urgent warning of collision, turn into another glider
> > which was not logged as a threat until the sudden evasive
> > turn was made. Technology might give the warning but
> > it is the human that has to react.
>
> These are not new questions, so you can be assured that people
> contemplating these systems are considering them. Systems do not spring
> fully featured and perfect from the mind of an engineer, but proceed
> through stages of development and testing. Exactly what problems and
> benefits will appear during this process can't be predicted very well.
>
> >
> > I personally don't think we have the technology or
> > expertise to design such a system or indeed the expertise
> > to put it in a small enough space to fit in a glider
> > right now, and the cost could be more than the average
> > glider is worth. I am not saying do nothing, what I
> > am saying is do something realistic and achievable
> > now. I have little doubt that what has been proposed
> > will be with us in 10 years time but it is now that
> > we have a problem.
> >
> > I stand by what I originally wrote, humans are the
> > cause of accidents, humans can prevent accidents. Whether
> > we have the will to do it is another matter entirely.
>
> What must we do? Propose something - we're listening.
>
Here's my modest proposal, eat them. Sorry, trying again--
Don't ask the system to figure collision potential and don't introduce
another screen. Just have a system call out "target NNW, same altitude,
closing @ x". If I see it, I say something like "clear" or "check" and the
system stops alerting me to the known target. If I don't acknowledge the
target the system continues to provide information at regular intervals to
help me find it.
I might be re-notified of "cleared" targets if we continue to fly in
proximity to one another.
Frankly, I can't imagine a user interface that would be useful in a large
gaggle. That's probably OK because that's where we're likely to be most
alert to this type of threat.

Brent

Eric Greenwell

May 3rd 04, 10:03 PM

303pilot wrote:

> "Eric Greenwell" > wrote in message

>>
>>Ony if you think the problem is 40 gliders instead of 3 or 4, which is
>>all that was involved in the recent collisions.
>>
>
> I'm not a programmer, but I work with them on a daily basis. It seems to me
> that even a 3 or 4 glider problem is highly complex because sailplanes fly
> in highly irregular paths.

But still more manageable the 40, right :} ? But to answer the
question, and keeping in mind I don't know any details of the Flarm
system, it may not be possible or necessary to have a TCAS-like system.
Though several gliders flying at random may indeed be complex, the
algorithms chosen can make simplifying assumptions based on the nature
of glider flight. Also, the pilot arriving at a thermal might modify his
arrival to keep the threat level low, compared to how he does it now, so
as not to "alarm" the pilots already in the thermal (and for other
situations, also, not just thermals).

We don't even fly straight point to point--we
> weave left and right, we dolphin. A ship might be going (more or less)
> straight and a couple hundred feet below me. Not a threat, right? Maybe,
> maybe not--what if I'm in a thermal and he's seen me and plans to join me.
> He suddenly converts speed to altitude and he's in my blind spot. My GPS
> has a 4 second polling cycle. Ooops.

Most GPS receivers we use emit at once a second, though _flight
recorders_ might record at a slower rate (the newer ones will also
record at once per second). Rate isn't a problem.

> What if two ships are in a thermal but maintaining separation. Everything's
> fine, right? Sure, until we get to the top of the lift band and he suddenly
> tightens his turn to go through the core as he heads out on course.

This simple situation is likely easy to handle. It should cause some
alarms in both cockpits, unless it is a diving exit, which would put him
well below the still thermalling glider!

I'm sure anyone contemplating these systems has thought of these
situations and more, and intends to cope with them, and use extensive
testing to validate the equipment. As I mentioned before, the equipment
might cause changes in pilot behavior, perhaps because they wish to
avoid causing alarms, or because they now realize better the dangers
involved.

>>Have you ever flown in a thermal with even 10 gliders? I have many
>>times. I can not keep track of even 10 gliders, but I can still thermal
>>safely when there are that many and more. We are not flying around at
>>random, but circling in an orderly fashion. Only the nearby gliders are
>>a threat that must be monitored. In any case, a system that deals with
>>only a few gliders will cover most of the situations.
>
> Orderly? To you and I yes. To a program? Not really.
> Think about what happens at cloudbase in a contest gaggle. The (mostly)
> orderly and similar actions (mostly same speed & bank angle) get more
> random. Some pilots increase their radius purposefully suboptimizing climb
> rates, others deploy a bit of spoiler, others leave. How are these actions
> to be predicted?
> Even if I have a 1 second polling rate on my GPS & "traffic
> analysis/collision avoidance system", how many variables can change in that
> one second and how fast can my safe separation be erased?

In one second? Very few. Gliders simply don't react quickly in roll, and
pilots don't pitch rapidly in the cloudbase gaggle. The ones I've been
in, everyone is changing direction smoothly and slowly. Away from a
gaggle, pitch changes can occur rapidly, but one second still seems
short enough to me. It would be better to seek the opinion of someone
actually attempting this, of course!

snip

>>What must we do? Propose something - we're listening.
>>
>
> Here's my modest proposal, eat them. Sorry, trying again--
> Don't ask the system to figure collision potential and don't introduce
> another screen. Just have a system call out "target NNW, same altitude,
> closing @ x". If I see it, I say something like "clear" or "check" and the
> system stops alerting me to the known target. If I don't acknowledge the
> target the system continues to provide information at regular intervals to
> help me find it.

If I were designing a system, I'd make this capability the first phase.
Perhaps it would be good enough. I'd try a button on the stick before
the confirmation.

> I might be re-notified of "cleared" targets if we continue to fly in
> proximity to one another.
> Frankly, I can't imagine a user interface that would be useful in a large
> gaggle. That's probably OK because that's where we're likely to be most
> alert to this type of threat.
>
> Brent
>
>

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Bill Daniels

May 3rd 04, 10:55 PM

The FLARM device not only provides traffic advisories, it tracks ground
hazards like towers and wires. It's also a IGC logger.

Most handheld computers do several million floating point operations per
second (MIPS) Hundreds of MIPS are available on low power CPU's. That's
enough to compute trajectories on 40+ gliders in the 1/2 second interval
between GPS fixes. Having enough computer power is not a problem.

There are a lot of smarter people than me who could do the programming but
maybe I can help with a flowchart.

Step one: Are there any targets within one kilometer? If yes, provide
count.

Step two: Are any of these targets within + or - 200 meters of my altitude?
If yes, proceed to step three. If not, ignore.

Step three: For any targets within + or - 200 meters of my altitude, is the
slant range increasing or decreasing? If increasing, ignore. If decreasing
go to step four.

Step four: For targets within +- 200 meters and closing, is the relative
bearing changing less than 10 degrees per second? If yes, sound alarm and
provide relative bearing and range. If greater, do nothing.

Step four is a bit of oversimplification, for example, the critical rate of
change for relative bearing increases for closer targets, which would
require a look-up table or formula. Still, this is not a complicated
algorithm.

Bill Daniels

"Eric Greenwell" > wrote in message
...
> 303pilot wrote:
>
> > "Eric Greenwell" > wrote in message
>
> >>
> >>Ony if you think the problem is 40 gliders instead of 3 or 4, which is
> >>all that was involved in the recent collisions.
> >>
> >
> > I'm not a programmer, but I work with them on a daily basis. It seems
to me
> > that even a 3 or 4 glider problem is highly complex because sailplanes
fly
> > in highly irregular paths.
>
> But still more manageable the 40, right :} ? But to answer the
> question, and keeping in mind I don't know any details of the Flarm
> system, it may not be possible or necessary to have a TCAS-like system.
> Though several gliders flying at random may indeed be complex, the
> algorithms chosen can make simplifying assumptions based on the nature
> of glider flight. Also, the pilot arriving at a thermal might modify his
> arrival to keep the threat level low, compared to how he does it now, so
> as not to "alarm" the pilots already in the thermal (and for other
> situations, also, not just thermals).
>
> We don't even fly straight point to point--we
> > weave left and right, we dolphin. A ship might be going (more or less)
> > straight and a couple hundred feet below me. Not a threat, right?
Maybe,
> > maybe not--what if I'm in a thermal and he's seen me and plans to join
me.
> > He suddenly converts speed to altitude and he's in my blind spot. My
GPS
> > has a 4 second polling cycle. Ooops.
>
> Most GPS receivers we use emit at once a second, though _flight
> recorders_ might record at a slower rate (the newer ones will also
> record at once per second). Rate isn't a problem.
>
> > What if two ships are in a thermal but maintaining separation.
Everything's
> > fine, right? Sure, until we get to the top of the lift band and he
suddenly
> > tightens his turn to go through the core as he heads out on course.
>
> This simple situation is likely easy to handle. It should cause some
> alarms in both cockpits, unless it is a diving exit, which would put him
> well below the still thermalling glider!
>
> I'm sure anyone contemplating these systems has thought of these
> situations and more, and intends to cope with them, and use extensive
> testing to validate the equipment. As I mentioned before, the equipment
> might cause changes in pilot behavior, perhaps because they wish to
> avoid causing alarms, or because they now realize better the dangers
> involved.
>
> >>Have you ever flown in a thermal with even 10 gliders? I have many
> >>times. I can not keep track of even 10 gliders, but I can still thermal
> >>safely when there are that many and more. We are not flying around at
> >>random, but circling in an orderly fashion. Only the nearby gliders are
> >>a threat that must be monitored. In any case, a system that deals with
> >>only a few gliders will cover most of the situations.
> >
> > Orderly? To you and I yes. To a program? Not really.
> > Think about what happens at cloudbase in a contest gaggle. The (mostly)
> > orderly and similar actions (mostly same speed & bank angle) get more
> > random. Some pilots increase their radius purposefully suboptimizing
climb
> > rates, others deploy a bit of spoiler, others leave. How are these
actions
> > to be predicted?
> > Even if I have a 1 second polling rate on my GPS & "traffic
> > analysis/collision avoidance system", how many variables can change in
that
> > one second and how fast can my safe separation be erased?
>
> In one second? Very few. Gliders simply don't react quickly in roll, and
> pilots don't pitch rapidly in the cloudbase gaggle. The ones I've been
> in, everyone is changing direction smoothly and slowly. Away from a
> gaggle, pitch changes can occur rapidly, but one second still seems
> short enough to me. It would be better to seek the opinion of someone
> actually attempting this, of course!
>
> snip
>
> >>What must we do? Propose something - we're listening.
> >>
> >
> > Here's my modest proposal, eat them. Sorry, trying again--
> > Don't ask the system to figure collision potential and don't introduce
> > another screen. Just have a system call out "target NNW, same altitude,
> > closing @ x". If I see it, I say something like "clear" or "check" and
the
> > system stops alerting me to the known target. If I don't acknowledge
the
> > target the system continues to provide information at regular intervals
to
> > help me find it.
>
> If I were designing a system, I'd make this capability the first phase.
> Perhaps it would be good enough. I'd try a button on the stick before
> the confirmation.
>
> > I might be re-notified of "cleared" targets if we continue to fly in
> > proximity to one another.
> > Frankly, I can't imagine a user interface that would be useful in a
large
> > gaggle. That's probably OK because that's where we're likely to be most
> > alert to this type of threat.
> >
> > Brent
> >
> >
>
> --
> Change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
> USA
>

Andy Blackburn

May 3rd 04, 11:26 PM

I can think of ways to filter for only the most proximate
threats, even in a gaggle (closest proximity, closing
rate, etc). What seems to me would be difficult in
a gaggle setting is figuring out what to do once everyone
starts maneuvering in response to alerts - it could
quickly get overwhelming.

Even so, more information is likely better than less
under most circumstances.

9B

At 21:12 03 May 2004, Eric Greenwell wrote:
>303pilot wrote:
>
>> 'Eric Greenwell' wrote in message
>
>>>
>>>Ony if you think the problem is 40 gliders instead
>>>of 3 or 4, which is
>>>all that was involved in the recent collisions.
>>>
>>
>> I'm not a programmer, but I work with them on a daily
>>basis. It seems to me
>> that even a 3 or 4 glider problem is highly complex
>>because sailplanes fly
>> in highly irregular paths.
>
>But still more manageable the 40, right :} ? But to
>answer the
>question, and keeping in mind I don't know any details
>of the Flarm
>system, it may not be possible or necessary to have
>a TCAS-like system.
>Though several gliders flying at random may indeed
>be complex, the
>algorithms chosen can make simplifying assumptions
>based on the nature
>of glider flight. Also, the pilot arriving at a thermal
>might modify his
>arrival to keep the threat level low, compared to how
>he does it now, so
>as not to 'alarm' the pilots already in the thermal
>(and for other
>situations, also, not just thermals).
>
> We don't even fly straight point to point--we
>> weave left and right, we dolphin. A ship might be
>>going (more or less)
>> straight and a couple hundred feet below me. Not
>>a threat, right? Maybe,
>> maybe not--what if I'm in a thermal and he's seen
>>me and plans to join me.
>> He suddenly converts speed to altitude and he's in
>>my blind spot. My GPS
>> has a 4 second polling cycle. Ooops.
>
>Most GPS receivers we use emit at once a second, though
>_flight
>recorders_ might record at a slower rate (the newer
>ones will also
>record at once per second). Rate isn't a problem.
>
>> What if two ships are in a thermal but maintaining
>>separation. Everything's
>> fine, right? Sure, until we get to the top of the
>>lift band and he suddenly
>> tightens his turn to go through the core as he heads
>>out on course.
>
>This simple situation is likely easy to handle. It
>should cause some
>alarms in both cockpits, unless it is a diving exit,
>which would put him
> well below the still thermalling glider!
>
>I'm sure anyone contemplating these systems has thought
>of these
>situations and more, and intends to cope with them,
>and use extensive
>testing to validate the equipment. As I mentioned before,
>the equipment
>might cause changes in pilot behavior, perhaps because
>they wish to
>avoid causing alarms, or because they now realize better
>the dangers
>involved.
>
>>>Have you ever flown in a thermal with even 10 gliders?
>>>I have many
>>>times. I can not keep track of even 10 gliders, but
>>>I can still thermal
>>>safely when there are that many and more. We are not
>>>flying around at
>>>random, but circling in an orderly fashion. Only the
>>>nearby gliders are
>>>a threat that must be monitored. In any case, a system
>>>that deals with
>>>only a few gliders will cover most of the situations.
>>
>> Orderly? To you and I yes. To a program? Not really.
>> Think about what happens at cloudbase in a contest
>>gaggle. The (mostly)
>> orderly and similar actions (mostly same speed & bank
>>angle) get more
>> random. Some pilots increase their radius purposefully
>>suboptimizing climb
>> rates, others deploy a bit of spoiler, others leave.
>> How are these actions
>> to be predicted?
>> Even if I have a 1 second polling rate on my GPS &
>>'traffic
>> analysis/collision avoidance system', how many variables
>>can change in that
>> one second and how fast can my safe separation be
>>erased?
>
>In one second? Very few. Gliders simply don't react
>quickly in roll, and
>pilots don't pitch rapidly in the cloudbase gaggle.
>The ones I've been
>in, everyone is changing direction smoothly and slowly.
>Away from a
>gaggle, pitch changes can occur rapidly, but one second
>still seems
>short enough to me. It would be better to seek the
>opinion of someone
>actually attempting this, of course!
>
>snip
>
>>>What must we do? Propose something - we're listening.
>>>
>>
>> Here's my modest proposal, eat them. Sorry, trying
>>again--
>> Don't ask the system to figure collision potential
>>and don't introduce
>> another screen. Just have a system call out 'target
>>NNW, same altitude,
>> closing @ x'. If I see it, I say something like 'clear'
>>or 'check' and the
>> system stops alerting me to the known target. If
>>I don't acknowledge the
>> target the system continues to provide information
>>at regular intervals to
>> help me find it.
>
>If I were designing a system, I'd make this capability
>the first phase.
>Perhaps it would be good enough. I'd try a button on
>the stick before
>the confirmation.
>
>> I might be re-notified of 'cleared' targets if we
>>continue to fly in
>> proximity to one another.
>> Frankly, I can't imagine a user interface that would
>>be useful in a large
>> gaggle. That's probably OK because that's where we're
>>likely to be most
>> alert to this type of threat.
>>
>> Brent
>>
>>
>
>--
>Change 'netto' to 'net' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
>

Bill Daniels

May 3rd 04, 11:48 PM

I don't think anyone would maneuver in response to the alert, they would
maneuver in response to what their eyes told them when they looked at the
threat in response to the alert.

Bill Daniels

"Andy Blackburn" > wrote in message
...
> I can think of ways to filter for only the most proximate
> threats, even in a gaggle (closest proximity, closing
> rate, etc). What seems to me would be difficult in
> a gaggle setting is figuring out what to do once everyone
> starts maneuvering in response to alerts - it could
> quickly get overwhelming.
>
> Even so, more information is likely better than less
> under most circumstances.
>
> 9B
>
>
> At 21:12 03 May 2004, Eric Greenwell wrote:
> >303pilot wrote:
> >
> >> 'Eric Greenwell' wrote in message
> >
> >>>
> >>>Ony if you think the problem is 40 gliders instead
> >>>of 3 or 4, which is
> >>>all that was involved in the recent collisions.
> >>>
> >>
> >> I'm not a programmer, but I work with them on a daily
> >>basis. It seems to me
> >> that even a 3 or 4 glider problem is highly complex
> >>because sailplanes fly
> >> in highly irregular paths.
> >
> >But still more manageable the 40, right :} ? But to
> >answer the
> >question, and keeping in mind I don't know any details
> >of the Flarm
> >system, it may not be possible or necessary to have
> >a TCAS-like system.
> >Though several gliders flying at random may indeed
> >be complex, the
> >algorithms chosen can make simplifying assumptions
> >based on the nature
> >of glider flight. Also, the pilot arriving at a thermal
> >might modify his
> >arrival to keep the threat level low, compared to how
> >he does it now, so
> >as not to 'alarm' the pilots already in the thermal
> >(and for other
> >situations, also, not just thermals).
> >
> > We don't even fly straight point to point--we
> >> weave left and right, we dolphin. A ship might be
> >>going (more or less)
> >> straight and a couple hundred feet below me. Not
> >>a threat, right? Maybe,
> >> maybe not--what if I'm in a thermal and he's seen
> >>me and plans to join me.
> >> He suddenly converts speed to altitude and he's in
> >>my blind spot. My GPS
> >> has a 4 second polling cycle. Ooops.
> >
> >Most GPS receivers we use emit at once a second, though
> >_flight
> >recorders_ might record at a slower rate (the newer
> >ones will also
> >record at once per second). Rate isn't a problem.
> >
> >> What if two ships are in a thermal but maintaining
> >>separation. Everything's
> >> fine, right? Sure, until we get to the top of the
> >>lift band and he suddenly
> >> tightens his turn to go through the core as he heads
> >>out on course.
> >
> >This simple situation is likely easy to handle. It
> >should cause some
> >alarms in both cockpits, unless it is a diving exit,
> >which would put him
> > well below the still thermalling glider!
> >
> >I'm sure anyone contemplating these systems has thought
> >of these
> >situations and more, and intends to cope with them,
> >and use extensive
> >testing to validate the equipment. As I mentioned before,
> >the equipment
> >might cause changes in pilot behavior, perhaps because
> >they wish to
> >avoid causing alarms, or because they now realize better
> >the dangers
> >involved.
> >
> >>>Have you ever flown in a thermal with even 10 gliders?
> >>>I have many
> >>>times. I can not keep track of even 10 gliders, but
> >>>I can still thermal
> >>>safely when there are that many and more. We are not
> >>>flying around at
> >>>random, but circling in an orderly fashion. Only the
> >>>nearby gliders are
> >>>a threat that must be monitored. In any case, a system
> >>>that deals with
> >>>only a few gliders will cover most of the situations.
> >>
> >> Orderly? To you and I yes. To a program? Not really.
> >> Think about what happens at cloudbase in a contest
> >>gaggle. The (mostly)
> >> orderly and similar actions (mostly same speed & bank
> >>angle) get more
> >> random. Some pilots increase their radius purposefully
> >>suboptimizing climb
> >> rates, others deploy a bit of spoiler, others leave.
> >> How are these actions
> >> to be predicted?
> >> Even if I have a 1 second polling rate on my GPS &
> >>'traffic
> >> analysis/collision avoidance system', how many variables
> >>can change in that
> >> one second and how fast can my safe separation be
> >>erased?
> >
> >In one second? Very few. Gliders simply don't react
> >quickly in roll, and
> >pilots don't pitch rapidly in the cloudbase gaggle.
> >The ones I've been
> >in, everyone is changing direction smoothly and slowly.
> >Away from a
> >gaggle, pitch changes can occur rapidly, but one second
> >still seems
> >short enough to me. It would be better to seek the
> >opinion of someone
> >actually attempting this, of course!
> >
> >snip
> >
> >>>What must we do? Propose something - we're listening.
> >>>
> >>
> >> Here's my modest proposal, eat them. Sorry, trying
> >>again--
> >> Don't ask the system to figure collision potential
> >>and don't introduce
> >> another screen. Just have a system call out 'target
> >>NNW, same altitude,
> >> closing @ x'. If I see it, I say something like 'clear'
> >>or 'check' and the
> >> system stops alerting me to the known target. If
> >>I don't acknowledge the
> >> target the system continues to provide information
> >>at regular intervals to
> >> help me find it.
> >
> >If I were designing a system, I'd make this capability
> >the first phase.
> >Perhaps it would be good enough. I'd try a button on
> >the stick before
> >the confirmation.
> >
> >> I might be re-notified of 'cleared' targets if we
> >>continue to fly in
> >> proximity to one another.
> >> Frankly, I can't imagine a user interface that would
> >>be useful in a large
> >> gaggle. That's probably OK because that's where we're
> >>likely to be most
> >> alert to this type of threat.
> >>
> >> Brent
> >>
> >>
> >
> >--
> >Change 'netto' to 'net' to email me directly
> >
> >Eric Greenwell
> >Washington State
> >USA
> >
> >
>
>
>

Mike Borgelt

May 4th 04, 12:51 AM

On Sun, 02 May 2004 00:19:47 GMT, "Bill Daniels" >
wrote:

>Yes I do fly in the vast empty skies of the western USA, thank goodness.
>However, I'm also a pilot who has survived a mid-air with another glider
>while flying in those "empty" skies.
>
>Try to picture this. The little device goes "Beep" and when you look at it,
>the 20mm 2-digit LED display says "06" meaning 6 gliders are within one
>kilometer. My reaction is to look outside like crazy until I can see all
>six. It beeps again and displays 07 meaning that another glider has joined
>the gaggle. I look even harder. This uses the "Mark 1 eyeball" to it's
>maximum.
>
>Extremely accurate GPS data has nothing to do with this. If the error is
>that the 7th glider is really 1.005 Km away instead of 1.000 why would I
>care? If a glider joins the gaggle without this device there is a very good
>chance I will see him while looking for the others even though the device
>does not detect him.
>
>It is not necessary to compute the trajectories of all gliders in the gaggle
>to determine those with a collision probability. Those 500 feet above and
>below present no danger whatsoever.
>
>Now picture an advanced version. The device still displays "07" but it now
>sounds "deedle, deedle, deedle" and an LED at 8 O'clock illuminates meaning
>that there is a non-zero probability collision threat at that relative
>bearing. The "Mark 1 eyeballs" leap into action and I look over my left
>shoulder to see that the other glider will pass clear. Is this a "false
>alarm"? Not really. I really wanted to see him if he was that close. I
>appreciated the "heads up". The device need only compute probabilities for
>those targets near and closing while near the same altitude.
>
>Perhaps the problem is calling this an "Anti-Collision Device" when it is
>really a situational awareness aid.
>
>As for battery life, perhaps you noticed the news that a fully IFR equipped
>Kestral 17 flown by Gordon Boettger flew 1562 Kilometers in 11:15 from
>Minden, Nevada, USA to Steamboat Springs, Colorado. Most of the flight was
>in wave above 20,000 feet. Gordon's Kestral was transponder equipped as
>well as carrying a lot of other electronics to operate legally in positive
>control airspace. Battery capacity didn't seem to be a problem.
>
>The device I'm talking about would weigh less than 200 gms and run on four
>AA batteries for 50+ hours. The amount of time spent looking at it will be
>fractions of a second and then only when critical information is displayed.
>
>Bill Daniels

"electronically enhanced see and avoid" is what we are really after
here, not a 100% guaranteed collision prevention system.

Nearly all gliders already have a GPS of some sort so part of the
hardware already exists.

For those who insist on greater than once per second updates go to the
Garmin website and look at the new Garmin 16A engine which provides 5
Hz updates. This is however, unnecessary.

As someone said here "the glider you don't see is the one that will
get you".(not necessarily true) An electronic system will help with
this which is why fighters got tail warning radar not long after the
invention of radar itself.

Advocating training or better behaviour by pilots probably won't work.
If it did we'd know by now. The collisions we have are the ones left
AFTER this has already been done. Could some people do better? - yes.

This has been going on for 90 years now. Ask the victims of Manfred
von Richthofen, Billy Bishop, Albert Ball and all the others. Even the
aces got surprised occasionally and survived by luck(Adolph Galland)
or not.

You don't need any display in the cockpit, just a voice.(no panel
space required) Some years ago we owned a Nimbus 3DM and it was
remarkable how often a second pair of eyes would pick up something
that one missed.
The electronic systems like FLARM will provide that second pair of
eyes in single seat gliders.

It isn't necessary to have a 100% system. We already do that with
parachutes and in the military, ejection seats. Neither are 100%
effective.

When the alternative is almost certain death even a 50% mitigator
looks good.

Any National gliding body responsible for regulation could trial such
a system at any given site and then go on to require its use
nationwide.

Mike Borgelt

Marc Ramsey

May 4th 04, 02:49 AM

Mike Borgelt wrote:
> "electronically enhanced see and avoid" is what we are really after
> here, not a 100% guaranteed collision prevention system.

I spent some time looking at this a few years ago. Basically, establish
two virtual "bubbles" around the glider. The device would announce (by
voice) the call sign, bearing, and relative altitude of a similarly
equipped glider which, given the present speeds and courses of both
gliders, will enter the smaller bubble within some number of seconds. A
second announcement would be made if entry is predicted within a second
shorter time interval. After that, the glider would be ignored until it
exits the larger bubble. The sizes of the bubbles and times could be
established by the pilot, and might vary according to speed or
cruise/climb mode. My thinking was that the smaller bubble would be
around 500 meters radius, the larger 1000 to 2000 meters, the longer
time interval 20 seconds, shorter interval 10 seconds. Some additional
"smarts" would be required to deal with announcing simultaneous
potential conflicts with several other gliders.

Initial examination showed that a fast 8 bit processor could actually do
the necessary calculations to track as many as 32 gliders with a 2
second update rate, Use of fixed point arithmetic, and table lookups for
transcendental functions (or a much faster processor) would have been
required.

What made me give up on the project was an inability to find suitable,
low cost, unlicensed, radio transceivers that could be used legally in
the US for this sort of application. One needs to transmit with enough
power to allow reliable tracking out to 5 km or so, and enough bandwidth
to allow a position broadcast duty cycle of around 1/128 (to allow
periodic position reports at randomized intervals, with reasonably low
probability of collision). A proof of concept could be done using
(licensed) amateur frequencies. But, the difficulties associated with
trying to produce a salable product seemed insurmountable.

Marc

Gerhard Wesp

May 4th 04, 08:52 AM

Bill Daniels > wrote:
> The FLARM device not only provides traffic advisories, it tracks ground
> hazards like towers and wires. It's also a IGC logger.

AFAIK it is not _yet_ an IGC logger. At the moment, the developers
concentrate on collision avoidance, IGC logger approval is secondary
priority.

Friday there'll be another meeting/presentation here at Zuerich with
news, updates and discussions.

FLARM does NOT provide to the pilot a count of targets in a certain
vicinity. A count is a minor factor for collision avoidance and can
easily lead to confusion (remember that only FLARM equipped A/C can be
targetted!).

-Gerhard

Dave Martin

May 4th 04, 09:11 AM

As one of those who is sceptical about the benefits
of an anticollision, I accept the comments made by
Mike and Bill. I hope the debate spurs those interested
in the development of an anti collision device or perhaps
a better description would a proximity alert to rpoduce
a working test model that can be evaluated.

Another area where we could impove survival of midairs
would be built in parachutes. I am sure that many
survival midairs accidents are not survived because
of the time taken to and the ability to get out of
a damaged aircraft quickly.

An in built parachute with automatic deployment would
surely help. Tests have been carried out and shown
to work.

Size and weight may be just part of the problem but
modern materials, would surely help to solve this.

Why it it that that, as yet, the devizes are not been
built into new gliders?

Dave

Bert Willing

May 4th 04, 09:59 AM

They are built into a couple of new gliders, you just need to be willing to
pay for it.

--
Bert Willing

ASW20 "TW"

"Dave Martin" > a écrit dans le message
de ...
> As one of those who is sceptical about the benefits
> of an anticollision, I accept the comments made by
> Mike and Bill. I hope the debate spurs those interested
> in the development of an anti collision device or perhaps
> a better description would a proximity alert to rpoduce
> a working test model that can be evaluated.
>
> Another area where we could impove survival of midairs
> would be built in parachutes. I am sure that many
> survival midairs accidents are not survived because
> of the time taken to and the ability to get out of
> a damaged aircraft quickly.
>
> An in built parachute with automatic deployment would
> surely help. Tests have been carried out and shown
> to work.
>
> Size and weight may be just part of the problem but
> modern materials, would surely help to solve this.
>
> Why it it that that, as yet, the devizes are not been
> built into new gliders?
>
> Dave
>
>
>
>
>
>

Don Johnstone

May 4th 04, 11:11 AM

At 23:00 03 May 2004, Bill Daniels wrote:
>I don't think anyone would maneuver in response to
>the alert, they would
>maneuver in response to what their eyes told them when
>they looked at the
>threat in response to the alert.

Sadly I think it is just what they would do, bit like
people braking violently when they see a GATSO (speed
cam) late, it matters not that they are within the
speed limit.
We have a rule in the UK that if we see a glider on
the approach with it's wheel still up we do not try
and call on the radio, it is thought that accidents
are caused by people being distracted and crashing
because they stopped concentrating on landing and tried
to lower the wheel, an automatic reaction. Undercarriage
warning horns are discouraged for the same reason.
I suspect a collision warning would be reacted to with
even more urgency and less thought. It is not that
we are unthinking people it is just that if someone
yells 'duck' we do.

I am sorry if my opion offends and seems negative but
the answer to this problem is a human one, better education,
better training, better awareness of the problem and
potential hazards and perhaps even a change in the
way we view flying close to each other.

My subjective view is that the majority of collisions
take place between aircraft that know exactly where
the other aircraft is yet still manage to make contact.
This is certainly true of the military who as I said
earlier are the only other significant organisation
that encourage aircraft to fly close together. I really
don't see how another gadget in the cockpit can help
unless it is very sophisticated indeed.

>
>Bill Daniels
>
>'Andy Blackburn' wrote in message
...
>> I can think of ways to filter for only the most proximate
>> threats, even in a gaggle (closest proximity, closing
>> rate, etc). What seems to me would be difficult in
>> a gaggle setting is figuring out what to do once everyone
>> starts maneuvering in response to alerts - it could
>> quickly get overwhelming.
>>
>> Even so, more information is likely better than less
>> under most circumstances.
>>
>> 9B
>>
>>
>> At 21:12 03 May 2004, Eric Greenwell wrote:
>> >303pilot wrote:
>> >
>> >> 'Eric Greenwell' wrote in message
>> >
>> >>>
>> >>>Ony if you think the problem is 40 gliders instead
>> >>>of 3 or 4, which is
>> >>>all that was involved in the recent collisions.
>> >>>
>> >>
>> >> I'm not a programmer, but I work with them on a daily
>> >>basis. It seems to me
>> >> that even a 3 or 4 glider problem is highly complex
>> >>because sailplanes fly
>> >> in highly irregular paths.
>> >
>> >But still more manageable the 40, right :} ? But
>>>to
>> >answer the
>> >question, and keeping in mind I don't know any details
>> >of the Flarm
>> >system, it may not be possible or necessary to have
>> >a TCAS-like system.
>> >Though several gliders flying at random may indeed
>> >be complex, the
>> >algorithms chosen can make simplifying assumptions
>> >based on the nature
>> >of glider flight. Also, the pilot arriving at a thermal
>> >might modify his
>> >arrival to keep the threat level low, compared to
>>>how
>> >he does it now, so
>> >as not to 'alarm' the pilots already in the thermal
>> >(and for other
>> >situations, also, not just thermals).
>> >
>> > We don't even fly straight point to point--we
>> >> weave left and right, we dolphin. A ship might be
>> >>going (more or less)
>> >> straight and a couple hundred feet below me. Not
>> >>a threat, right? Maybe,
>> >> maybe not--what if I'm in a thermal and he's seen
>> >>me and plans to join me.
>> >> He suddenly converts speed to altitude and he's in
>> >>my blind spot. My GPS
>> >> has a 4 second polling cycle. Ooops.
>> >
>> >Most GPS receivers we use emit at once a second, though
>> >_flight
>> >recorders_ might record at a slower rate (the newer
>> >ones will also
>> >record at once per second). Rate isn't a problem.
>> >
>> >> What if two ships are in a thermal but maintaining
>> >>separation. Everything's
>> >> fine, right? Sure, until we get to the top of the
>> >>lift band and he suddenly
>> >> tightens his turn to go through the core as he heads
>> >>out on course.
>> >
>> >This simple situation is likely easy to handle. It
>> >should cause some
>> >alarms in both cockpits, unless it is a diving exit,
>> >which would put him
>> > well below the still thermalling glider!
>> >
>> >I'm sure anyone contemplating these systems has thought
>> >of these
>> >situations and more, and intends to cope with them,
>> >and use extensive
>> >testing to validate the equipment. As I mentioned
>>>before,
>> >the equipment
>> >might cause changes in pilot behavior, perhaps because
>> >they wish to
>> >avoid causing alarms, or because they now realize
>>>better
>> >the dangers
>> >involved.
>> >
>> >>>Have you ever flown in a thermal with even 10 gliders?
>> >>>I have many
>> >>>times. I can not keep track of even 10 gliders, but
>> >>>I can still thermal
>> >>>safely when there are that many and more. We are not
>> >>>flying around at
>> >>>random, but circling in an orderly fashion. Only the
>> >>>nearby gliders are
>> >>>a threat that must be monitored. In any case, a system
>> >>>that deals with
>> >>>only a few gliders will cover most of the situations.
>> >>
>> >> Orderly? To you and I yes. To a program? Not really.
>> >> Think about what happens at cloudbase in a contest
>> >>gaggle. The (mostly)
>> >> orderly and similar actions (mostly same speed &
>>>>bank
>> >>angle) get more
>> >> random. Some pilots increase their radius purposefully
>> >>suboptimizing climb
>> >> rates, others deploy a bit of spoiler, others leave.
>> >> How are these actions
>> >> to be predicted?
>> >> Even if I have a 1 second polling rate on my GPS
>>>>&
>> >>'traffic
>> >> analysis/collision avoidance system', how many variables
>> >>can change in that
>> >> one second and how fast can my safe separation be
>> >>erased?
>> >
>> >In one second? Very few. Gliders simply don't react
>> >quickly in roll, and
>> >pilots don't pitch rapidly in the cloudbase gaggle.
>> >The ones I've been
>> >in, everyone is changing direction smoothly and slowly.
>> >Away from a
>> >gaggle, pitch changes can occur rapidly, but one second
>> >still seems
>> >short enough to me. It would be better to seek the
>> >opinion of someone
>> >actually attempting this, of course!
>> >
>> >snip
>> >
>> >>>What must we do? Propose something - we're listening.
>> >>>
>> >>
>> >> Here's my modest proposal, eat them. Sorry, trying
>> >>again--
>> >> Don't ask the system to figure collision potential
>> >>and don't introduce
>> >> another screen. Just have a system call out 'target
>> >>NNW, same altitude,
>> >> closing @ x'. If I see it, I say something like
>>>>'clear'
>> >>or 'check' and the
>> >> system stops alerting me to the known target. If
>> >>I don't acknowledge the
>> >> target the system continues to provide information
>> >>at regular intervals to
>> >> help me find it.
>> >
>> >If I were designing a system, I'd make this capability
>> >the first phase.
>> >Perhaps it would be good enough. I'd try a button
>>>on
>> >the stick before
>> >the confirmation.
>> >
>> >> I might be re-notified of 'cleared' targets if we
>> >>continue to fly in
>> >> proximity to one another.
>> >> Frankly, I can't imagine a user interface that would
>> >>be useful in a large
>> >> gaggle. That's probably OK because that's where
>>>>we're
>> >>likely to be most
>> >> alert to this type of threat.
>> >>
>> >> Brent
>> >>
>> >>
>> >
>> >--
>> >Change 'netto' to 'net' to email me directly
>> >
>> >Eric Greenwell
>> >Washington State
>> >USA
>> >
>> >
>>
>>
>>
>
>

Robert Ehrlich

May 4th 04, 03:44 PM

Bill Daniels wrote:
> ...
> 1, There are (n) gliders in close proximity - say 1 kilometer. Even simple
> GPS broadcast devices should be able to determine the number of gliders
> nearby. It should beep softly when the number changes. (If the device says
> there are 3 gliders nearby and you can only see 2, you need to keep
> looking.)
>

The GPS position itself should be optional. i.e. if a GPS is available and
a GPS position available from it, the device should send it, but in any
case send an ID of the glider (e.g. its registration number or its tail number,
or both), so that even if you don't know exactly where another glider is, you
know that there is a glider nearby, as the power of the device makes that
you receive only broadcasts from near gliders.

Robert Ehrlich

May 4th 04, 04:18 PM

Michel Talon wrote:
>
> Jeff Dorwart > wrote:
> >
>
> Let me mention an important factor here, the age of the pilot.
> I have constated on myself that as one ages, the field of vision
> becomes narrower, not to mention that attention is not of the same
> quality, reflexes become poor, etc. This could well be one of the most
> important factors at play here. Sooaring is much much bettre fitted to
> young people in excellent health and doing a lot of sports (i mean
> sports like squash) than to old people.
>

But mostly old people have the time and money for gliding. In my
personal case, I am well aware of my declining capabilities, but
I think the lot of free time I can (and do) devote to gliding
compensates for that, i.e. if I had started gliding betweeen
15 and 50, I would have been flying less than 50 hours per
year (now over 200) and this factor overrides the decline due
to age.

Andy Durbin

May 4th 04, 05:27 PM

Dave Martin > wrote in message >
> An in built parachute with automatic deployment would
> surely help. Tests have been carried out and shown
> to work.

Manually deployed built-in parachutes have been tested and shown to
work in controlled conditions. I am not aware that anyone has
developed or demonstrated an automatic deployment parachute for
gliders.

Schleicher offered a ballistic chute option in the marketing brochures
for the ASW-28. As far as I know it was never an available option. I
heard the testing showed problems. Anyone know details.

Andy

Michel Talon

May 4th 04, 05:33 PM

Robert Ehrlich > wrote:
> Michel Talon wrote:
>>
>> Jeff Dorwart > wrote:
>> >
>>
>> Let me mention an important factor here, the age of the pilot.
>> I have constated on myself that as one ages, the field of vision
>> becomes narrower, not to mention that attention is not of the same
>> quality, reflexes become poor, etc. This could well be one of the most
>> important factors at play here. Sooaring is much much bettre fitted to
>> young people in excellent health and doing a lot of sports (i mean
>> sports like squash) than to old people.
>>
>
> But mostly old people have the time and money for gliding. In my
> personal case, I am well aware of my declining capabilities, but
> I think the lot of free time I can (and do) devote to gliding
> compensates for that, i.e. if I had started gliding betweeen
> 15 and 50, I would have been flying less than 50 hours per
> year (now over 200) and this factor overrides the decline due
> to age.

I don't think so. I remarked that a fair number of people whom i
learnt killed themselves soaring, were "well known famous" pilots,
flying a lot, but getting older. And, yes, since the soaring pilots
population is indeed getting older, thanks to the effect you mention
(time and money), it could well be that the number of accidents
augment, if this theory is true, of course.

--

Michel TALON

Don Johnstone

May 4th 04, 07:17 PM

Dear Michel

Over 90% of people who go into Old Peoples Homes die
there
Over 80% of people die in bed
Over 30% of people who go into hospital die

To live you need to avoid going into hospital, going
to bed or going into a home.
You are right older people do fly more they have more
time they are likely to have more accidents through
that factor alone. This argument is not likely to
be won by ageist ramblings.

Statistics are like lamposts, more for illumination
than leaning on.

At 16:48 04 May 2004, Michel Talon wrote:
>Robert Ehrlich wrote:
>> Michel Talon wrote:
>>>
>>> Jeff Dorwart wrote:
>>> >
>>>
>>> Let me mention an important factor here, the age of
>>>the pilot.
>>> I have constated on myself that as one ages, the field
>>>of vision
>>> becomes narrower, not to mention that attention is
>>>not of the same
>>> quality, reflexes become poor, etc. This could well
>>>be one of the most
>>> important factors at play here. Sooaring is much much
>>>bettre fitted to
>>> young people in excellent health and doing a lot of
>>>sports (i mean
>>> sports like squash) than to old people.
>>>
>>
>> But mostly old people have the time and money for
>>gliding. In my
>> personal case, I am well aware of my declining capabilities,
>>but
>> I think the lot of free time I can (and do) devote
>>to gliding
>> compensates for that, i.e. if I had started gliding
>>betweeen
>> 15 and 50, I would have been flying less than 50 hours
>>per
>> year (now over 200) and this factor overrides the
>>decline due
>> to age.
>
>I don't think so. I remarked that a fair number of
>people whom i
>learnt killed themselves soaring, were 'well known
>famous' pilots,
>flying a lot, but getting older. And, yes, since the
>soaring pilots
>population is indeed getting older, thanks to the effect
>you mention
>(time and money), it could well be that the number
>of accidents
>augment, if this theory is true, of course.
>
>
>--
>
>Michel TALON
>
>

Tony Verhulst

May 4th 04, 07:40 PM

> Statistics are like lamposts, more for illumination
> than leaning on.

The Mark Twain quote is:

Most people use statistics the way a drunk uses a lamppost:
more for support than for illumination.

Don Johnstone

May 4th 04, 09:44 PM

Thank you Tony, no offence meant to Mark Twain :-)
a fine writer.

At 18:54 04 May 2004, Tony Verhulst wrote:
>
>> Statistics are like lamposts, more for illumination
>> than leaning on.
>
>The Mark Twain quote is:
>
>Most people use statistics the way a drunk uses a lamppost:
>more for support than for illumination.
>
>

Jeff

May 4th 04, 10:51 PM

It is distressing that my name keeps getting carried over with a bunch
of comments I did not make. It appears from my accidental inclusion
(as my comments at the beginning of this thread have no statistics nor
references to age)in this diatribe that I have an ax to grind with
aging glider pilots while those who know me realize that I am a member
of this very group.

jeff

Don Johnstone > wrote in message >...
> Dear Michel
>
> Over 90% of people who go into Old Peoples Homes die
> there
> Over 80% of people die in bed
> Over 30% of people who go into hospital die
>
> To live you need to avoid going into hospital, going
> to bed or going into a home.
> You are right older people do fly more they have more
> time they are likely to have more accidents through
> that factor alone. This argument is not likely to
> be won by ageist ramblings.
>
> Statistics are like lamposts, more for illumination
> than leaning on.
>
>
>
> At 16:48 04 May 2004, Michel Talon wrote:
> >Robert Ehrlich wrote:
> >> Michel Talon wrote:
> >>>
> >>> Jeff Dorwart wrote:
> >>> >
> >>>
> >>> Let me mention an important factor here, the age of
> >>>the pilot.
> >>> I have constated on myself that as one ages, the field
> >>>of vision
> >>> becomes narrower, not to mention that attention is
> >>>not of the same
> >>> quality, reflexes become poor, etc. This could well
> >>>be one of the most
> >>> important factors at play here. Sooaring is much much
> >>>bettre fitted to
> >>> young people in excellent health and doing a lot of
> >>>sports (i mean
> >>> sports like squash) than to old people.
> >>>
> >>
> >> But mostly old people have the time and money for
> >>gliding. In my
> >> personal case, I am well aware of my declining capabilities,
> >>but
> >> I think the lot of free time I can (and do) devote
> >>to gliding
> >> compensates for that, i.e. if I had started gliding
> >>betweeen
> >> 15 and 50, I would have been flying less than 50 hours
> >>per
> >> year (now over 200) and this factor overrides the
> >>decline due
> >> to age.
> >
> >I don't think so. I remarked that a fair number of
> >people whom i
> >learnt killed themselves soaring, were 'well known
> >famous' pilots,
> >flying a lot, but getting older. And, yes, since the
> >soaring pilots
> >population is indeed getting older, thanks to the effect
> >you mention
> >(time and money), it could well be that the number
> >of accidents
> >augment, if this theory is true, of course.
> >
> >
> >--
> >
> >Michel TALON
> >
> >

Jeff

May 4th 04, 11:51 PM

The BRS website lists the Russia AC-4 and the Mechta as aircraft they
have mounted the BRS system into. I have been unable to track down
the specific aircraft involved.

jeff

(Andy Durbin) wrote in message >...
> Dave Martin > wrote in message >
> > An in built parachute with automatic deployment would
> > surely help. Tests have been carried out and shown
> > to work.
>
>
> Manually deployed built-in parachutes have been tested and shown to
> work in controlled conditions. I am not aware that anyone has
> developed or demonstrated an automatic deployment parachute for
> gliders.
>
> Schleicher offered a ballistic chute option in the marketing brochures
> for the ASW-28. As far as I know it was never an available option. I
> heard the testing showed problems. Anyone know details.
>
>
> Andy

Dave Houlton

May 5th 04, 12:45 AM

Don Johnstone wrote:
>
< snip >
>
> I am sorry if my opion offends and seems negative but
> the answer to this problem is a human one, better education,
> better training, better awareness of the problem and
> potential hazards and perhaps even a change in the
> way we view flying close to each other.

Don, I'm not offended by your opinion - I just don't understand it.
Better everything would be, well... better - but it's a goal that has
existed forever and it hasn't answered the problem yet. Perfect
education, perfect training, perfect awareness, etc. would be an answer,
but it's just not available. Lets be honest with ourselves - in the
real world of jobs, families, weather, and long commutes to the
gliderport all of those betters are just *not* going to happen, at least
not in any systemic way.

> My subjective view is that the majority of collisions
> take place between aircraft that know exactly where
> the other aircraft is yet still manage to make contact.
> This is certainly true of the military who as I said
> earlier are the only other significant organisation
> that encourage aircraft to fly close together. I really
> don't see how another gadget in the cockpit can help
> unless it is very sophisticated indeed.

Let's try on another analogy and see how it fits - automobiles.
Hundreds of modestly-trained individuals moving in tight formation,
passing within a meter of one another, closure rates of 200+ kph, etc.
Horribly complex to analyze, and no system has yet been invented that
will recognize a bad situation and reliably guide the driver out of it.
Thankfully, rather than say "can't be done - let's have some more
driver education" the auto industry has provided any number of safety
"gadgets" such as airbags, anti-lock brakes, traction control, proximity
radar, and on and on. For each individual gadget there are plenty of
straw-man situations that can be conjectured for which the gadget
doesn't help, but of much greater significance are the lives saved in
situations where the gadget *did* help.

No one advocating the FLARM or other hypothetical system thinks it can
safely guide a pilot out of *all* possible collision situations - let's
stop debating it's usefulness in a 40-ship gaggle. Can we agree that
there are *some* or perhaps *many* situations where it could help, and
were it available and widely deployed today at least *some* of this
year's mid-airs might have been avoided.

I'd buy one.

Dave