Transponders

[Mil80C]

A question to you fine soaring fraternity, what would your response be to
someone who suggested that it might be feasable to run a transponder in a
glider with a pedal generator?

--
BEER! So much more than just a breakfast drink!

[Vaughn Simon]

"Mil80C" > wrote in message
...
> A question to you fine soaring fraternity, what would your response be to
> someone who suggested that it might be feasable to run a transponder in a
> glider with a pedal generator?

A raised eyebrow, a polite silence, a glance at my wris****ch, followed
by a graceful withdrawal.

Vaughn


>
> --
> BEER! So much more than just a breakfast drink!
>
>

[Ben Flewett]

Are you on drugs? This is a bad idea for so, so many
reasons. Here are a few...

1. I don't want to pedal.
2. My feet are busy operating the rudder.
3. My cockpit is a constant state of crisis, which
allows no time for pedalling.
4. I sometimes fly in airspace for hours at a time.
I resent have to move the stick for hours at a time,
let alone having to pedal for hours at a time.
5. Weight.
6. Complexity.
7. I like a simple life.
8. I don't want a bearded sandal wearer installing
weird science contraptions in my glider.

Here's an idea. Why not use a battery?


At 15:00 21 January 2004, Vaughn Simon wrote:
>
>'Mil80C' wrote in message
...
>> A question to you fine soaring fraternity, what would
>>your response be to
>> someone who suggested that it might be feasable to
>>run a transponder in a
>> glider with a pedal generator?
>
> A raised eyebrow, a polite silence, a glance at
>my wris****ch, followed
>by a graceful withdrawal.
>
>Vaughn
>
>
>>
>> --
>> BEER! So much more than just a breakfast drink!
>>
>>
>
>
>

[Liam Finley]

"Mil80C" > wrote in message >...
> A question to you fine soaring fraternity, what would your response be to
> someone who suggested that it might be feasable to run a transponder in a
> glider with a pedal generator?

That's a brilliant idea.

Here's an even better one: power the transponder with a little
hamster running in a wheel connected to a generator.

Why not equip the glider with a second hamster to power a boundary
layer suction device, or perhaps an external propeller?

[Graham Wardell]

I know some pilots who would be good at it. Just connect it to their rudder
pedals!

"Mil80C" > wrote in message
...
> A question to you fine soaring fraternity, what would your response be to
> someone who suggested that it might be feasable to run a transponder in a
> glider with a pedal generator?
>
> --
> BEER! So much more than just a breakfast drink!
>
>

[BTIZ]

> Why not equip the glider with a second hamster to power a boundary
> layer suction device, or perhaps an external propeller?

would it then be a glider?

I wonder how much drag a RAT would create.. power all the stuff on a Ram Air
Turbine generator...

LOL

BT

[Jack]

On 04/01/21 07:45, in article
, "Mil80C"
> wrote:

> A question to you fine soaring fraternity, what would your response be to
> someone who suggested that it might be feasable to run a transponder in a
> glider with a pedal generator?

I'd say he's noticed my rudder coordination efforts.


-------
Jack
-------

[CH]

and how long does the battery last?
with the transponder on?

Australia decided, that planes without a permanent source
of power on board, do not need transponders in mixed
airspace.

I would prefer, that IFR traffic out of airport airspace should
fly higher than the convection height from sunrise to sunset :-)
How's that??
Chris


"Ben Flewett" > wrote in message
...
> Are you on drugs? This is a bad idea for so, so many
> reasons. Here are a few...
>
> 1. I don't want to pedal.
> 2. My feet are busy operating the rudder.
> 3. My cockpit is a constant state of crisis, which
> allows no time for pedalling.
> 4. I sometimes fly in airspace for hours at a time.
> I resent have to move the stick for hours at a time,
> let alone having to pedal for hours at a time.
> 5. Weight.
> 6. Complexity.
> 7. I like a simple life.
> 8. I don't want a bearded sandal wearer installing
> weird science contraptions in my glider.
>
> Here's an idea. Why not use a battery?
>
>
> At 15:00 21 January 2004, Vaughn Simon wrote:
> >
> >'Mil80C' wrote in message
> ...
> >> A question to you fine soaring fraternity, what would
> >>your response be to
> >> someone who suggested that it might be feasable to
> >>run a transponder in a
> >> glider with a pedal generator?
> >
> > A raised eyebrow, a polite silence, a glance at
> >my wris****ch, followed
> >by a graceful withdrawal.
> >
> >Vaughn
> >
> >
> >>
> >> --
> >> BEER! So much more than just a breakfast drink!
> >>
> >>
> >
> >
> >
>
>
>

[Mark James Boyd]

Hmmm...I wonder how big solar panels would need to be to generate
the needed power. The wings have a lot of area...

They make some very thin panels, but incorporating them into the
body might be quite tricky.

How about one on the dash, or right above the pilot's
bald spot? Could give some shade too!

[Eric Greenwell]

CH wrote:
> and how long does the battery last?
> with the transponder on?

A modern transponder like the Becker or Microaire draws about 600 ma
with an encoder. People report getting 5 and 6 hour flights on a 7
amphour battery, and still plenty of power left.
>
> Australia decided, that planes without a permanent source
> of power on board, do not need transponders in mixed
> airspace.
>
> I would prefer, that IFR traffic out of airport airspace should
> fly higher than the convection height from sunrise to sunset :-)
> How's that??
> Chris

Aye, and that's the rub: they come down to the airport, don't they? And
the airport airspace doesn't go all the way up to 18000 here in the USA,
but only to about 10,000 or so. And the buggers don't drop down into the
top, but slide in from the side. Can you believe it?

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

Eric Greenwell
Washington State
USA

[bumper]

How long the battery lasts will depend on how big it is (yes Virginia,
bigger is better), what its state of charge and condition is, what the
current draw of the transponder is (don't forget the blind encoder), what
the interrogation rate is, and if you also have solar panels . . . oh, and
how fast you pedal.
--
bumper ZZ (reverse all after @)>
"Dare to be different . . . circle in sink."


"CH" > wrote in message
...
> and how long does the battery last?
> with the transponder on?
>
> Australia decided, that planes without a permanent source
> of power on board, do not need transponders in mixed
> airspace.
>
> I would prefer, that IFR traffic out of airport airspace should
> fly higher than the convection height from sunrise to sunset :-)
> How's that??
> Chris
>
>
> "Ben Flewett" > wrote in message
> ...
> > Are you on drugs? This is a bad idea for so, so many
> > reasons. Here are a few...
> >
> > 1. I don't want to pedal.
> > 2. My feet are busy operating the rudder.
> > 3. My cockpit is a constant state of crisis, which
> > allows no time for pedalling.
> > 4. I sometimes fly in airspace for hours at a time.
> > I resent have to move the stick for hours at a time,
> > let alone having to pedal for hours at a time.
> > 5. Weight.
> > 6. Complexity.
> > 7. I like a simple life.
> > 8. I don't want a bearded sandal wearer installing
> > weird science contraptions in my glider.
> >
> > Here's an idea. Why not use a battery?
> >
> >
> > At 15:00 21 January 2004, Vaughn Simon wrote:
> > >
> > >'Mil80C' wrote in message
> > ...
> > >> A question to you fine soaring fraternity, what would
> > >>your response be to
> > >> someone who suggested that it might be feasable to
> > >>run a transponder in a
> > >> glider with a pedal generator?
> > >
> > > A raised eyebrow, a polite silence, a glance at
> > >my wris****ch, followed
> > >by a graceful withdrawal.
> > >
> > >Vaughn
> > >
> > >
> > >>
> > >> --
> > >> BEER! So much more than just a breakfast drink!
> > >>
> > >>
> > >
> > >
> > >
> >
> >
> >
>
>

[Ramy Yanetz]

$30 will get you an extra battery which will run your transponder longer
than you can stay in the air. Unfortunately many pilots as well as the FAA
don't know this.

Ramy


"CH" > wrote in message
...
> and how long does the battery last?
> with the transponder on?
>
> Australia decided, that planes without a permanent source
> of power on board, do not need transponders in mixed
> airspace.
>
> I would prefer, that IFR traffic out of airport airspace should
> fly higher than the convection height from sunrise to sunset :-)
> How's that??
> Chris
>
>
> "Ben Flewett" > wrote in message
> ...
> > Are you on drugs? This is a bad idea for so, so many
> > reasons. Here are a few...
> >
> > 1. I don't want to pedal.
> > 2. My feet are busy operating the rudder.
> > 3. My cockpit is a constant state of crisis, which
> > allows no time for pedalling.
> > 4. I sometimes fly in airspace for hours at a time.
> > I resent have to move the stick for hours at a time,
> > let alone having to pedal for hours at a time.
> > 5. Weight.
> > 6. Complexity.
> > 7. I like a simple life.
> > 8. I don't want a bearded sandal wearer installing
> > weird science contraptions in my glider.
> >
> > Here's an idea. Why not use a battery?
> >
> >
> > At 15:00 21 January 2004, Vaughn Simon wrote:
> > >
> > >'Mil80C' wrote in message
> > ...
> > >> A question to you fine soaring fraternity, what would
> > >>your response be to
> > >> someone who suggested that it might be feasable to
> > >>run a transponder in a
> > >> glider with a pedal generator?
> > >
> > > A raised eyebrow, a polite silence, a glance at
> > >my wris****ch, followed
> > >by a graceful withdrawal.
> > >
> > >Vaughn
> > >
> > >
> > >>
> > >> --
> > >> BEER! So much more than just a breakfast drink!
> > >>
> > >>
> > >
> > >
> > >
> >
> >
> >
>
>

[Ben Flewett]

I have two batteries and have flown for many hours
on transponder - no problem. The drain is higher if
you use mode C (height encoding) but still no problem.




At 05:42 22 January 2004, Ch wrote:
>and how long does the battery last?
>with the transponder on?
>
>Australia decided, that planes without a permanent
>source
>of power on board, do not need transponders in mixed
>airspace.
>
>I would prefer, that IFR traffic out of airport airspace
>should
>fly higher than the convection height from sunrise
>to sunset :-)
>How's that??
>Chris
>
>
>'Ben Flewett' wrote in message
...
>> Are you on drugs? This is a bad idea for so, so many
>> reasons. Here are a few...
>>
>> 1. I don't want to pedal.
>> 2. My feet are busy operating the rudder.
>> 3. My cockpit is a constant state of crisis, which
>> allows no time for pedalling.
>> 4. I sometimes fly in airspace for hours at a time.
>> I resent have to move the stick for hours at a time,
>> let alone having to pedal for hours at a time.
>> 5. Weight.
>> 6. Complexity.
>> 7. I like a simple life.
>> 8. I don't want a bearded sandal wearer installing
>> weird science contraptions in my glider.
>>
>> Here's an idea. Why not use a battery?
>>
>>
>> At 15:00 21 January 2004, Vaughn Simon wrote:
>> >
>> >'Mil80C' wrote in message
>> ...
>> >> A question to you fine soaring fraternity, what would
>> >>your response be to
>> >> someone who suggested that it might be feasable to
>> >>run a transponder in a
>> >> glider with a pedal generator?
>> >
>> > A raised eyebrow, a polite silence, a glance
>>>at
>> >my wris****ch, followed
>> >by a graceful withdrawal.
>> >
>> >Vaughn
>> >
>> >
>> >>
>> >> --
>> >> BEER! So much more than just a breakfast drink!
>> >>
>> >>
>> >
>> >
>> >
>>
>>
>>
>
>
>

[Mil80C]

Thanks all for your responses, the idea was posted in another NG and as I am
not of the soaring fraternaty, could not speak against it with any
experience. I will say that as an ATC, I will allways support your sport.

"Ramy Yanetz" > wrote in message
om...
> $30 will get you an extra battery which will run your transponder longer
> than you can stay in the air. Unfortunately many pilots as well as the FAA
> don't know this.
>
> Ramy
>
>
> "CH" > wrote in message
> ...
> > and how long does the battery last?
> > with the transponder on?
> >
> > Australia decided, that planes without a permanent source
> > of power on board, do not need transponders in mixed
> > airspace.
> >
> > I would prefer, that IFR traffic out of airport airspace should
> > fly higher than the convection height from sunrise to sunset :-)
> > How's that??
> > Chris
> >
> >
> > "Ben Flewett" > wrote in message
> > ...
> > > Are you on drugs? This is a bad idea for so, so many
> > > reasons. Here are a few...
> > >
> > > 1. I don't want to pedal.
> > > 2. My feet are busy operating the rudder.
> > > 3. My cockpit is a constant state of crisis, which
> > > allows no time for pedalling.
> > > 4. I sometimes fly in airspace for hours at a time.
> > > I resent have to move the stick for hours at a time,
> > > let alone having to pedal for hours at a time.
> > > 5. Weight.
> > > 6. Complexity.
> > > 7. I like a simple life.
> > > 8. I don't want a bearded sandal wearer installing
> > > weird science contraptions in my glider.
> > >
> > > Here's an idea. Why not use a battery?
> > >
> > >
> > > At 15:00 21 January 2004, Vaughn Simon wrote:
> > > >
> > > >'Mil80C' wrote in message
> > > ...
> > > >> A question to you fine soaring fraternity, what would
> > > >>your response be to
> > > >> someone who suggested that it might be feasable to
> > > >>run a transponder in a
> > > >> glider with a pedal generator?
> > > >
> > > > A raised eyebrow, a polite silence, a glance at
> > > >my wris****ch, followed
> > > >by a graceful withdrawal.
> > > >
> > > >Vaughn
> > > >
> > > >
> > > >>
> > > >> --
> > > >> BEER! So much more than just a breakfast drink!
> > > >>
> > > >>
> > > >
> > > >
> > > >
> > >
> > >
> > >
> >
> >
>
>

[Chris Nicholas]

Mil80c > , another point you need to be
aware of;

Many gliders, e.g. mine (a Ka6E), have neither panel space for a
transponder nor capability of carrying any more weight for the extra
batteries - I am already on max AUW, on a CofA which has already been
extended as far as it can be - I am 208 pounds with a parachute, and
there are plenty of heavier pilots than that.

If a new generation of lightweight, low power transponders emerges (the
UK CAA has persuaded one manufacturer to build a prototype which tested
OK), and if ICAO accept 20 w output instead of 100+, and if the thing is
taken to commercial production, and if it can come with an option of a
small remote control panel I could strap to my knee, with the larger
piece and battery going into the stowage behind the pilot's seat, and if
I can lose enought weight to compensate for it, then it might be viable.

I'm not holding my breath while we wait for all that to happen.

Regards - Chris N.

[Robert Ehrlich]

Chris Nicholas wrote:
>
> Mil80c > , another point you need to be
> aware of;
>
> Many gliders, e.g. mine (a Ka6E), have neither panel space for a
> transponder nor capability of carrying any more weight for the extra
> batteries - I am already on max AUW, on a CofA which has already been
> extended as far as it can be - I am 208 pounds with a parachute, and
> there are plenty of heavier pilots than that.
>
> If a new generation of lightweight, low power transponders emerges (the
> UK CAA has persuaded one manufacturer to build a prototype which tested
> OK), and if ICAO accept 20 w output instead of 100+, and if the thing is
> taken to commercial production, and if it can come with an option of a
> small remote control panel I could strap to my knee, with the larger
> piece and battery going into the stowage behind the pilot's seat, and if
> I can lose enought weight to compensate for it, then it might be viable.
>
> I'm not holding my breath while we wait for all that to happen.
>
> Regards - Chris N.

An experiment in the french Alps made with a group of tow planes
mimicking glider flight, i.e. circling together from time to time has
shown that transponders, except in mode S, may not be very useful in
gliders. As soon as 2 or more gliders are close together, e.g. circling
in the same thermal of working together the same ridge, they are hit
simultaneaously by the radar beam and generate simultaneaously their
responses, which results in both interfering and nothing useful
received at ATC. I had the chance of having one of the engineers
involved in the experiment as a passenger last September and he confirmed
this. In mode S, as each transponder is specifically adressable,
this mess will probably not occur, a new experiment using them is
planned.

[Marc Ramsey]

Robert Ehrlich wrote:
> An experiment in the french Alps made with a group of tow planes
> mimicking glider flight, i.e. circling together from time to time has
> shown that transponders, except in mode S, may not be very useful in
> gliders. As soon as 2 or more gliders are close together, e.g. circling
> in the same thermal of working together the same ridge, they are hit
> simultaneaously by the radar beam and generate simultaneaously their
> responses, which results in both interfering and nothing useful
> received at ATC. I had the chance of having one of the engineers
> involved in the experiment as a passenger last September and he confirmed
> this. In mode S, as each transponder is specifically adressable,
> this mess will probably not occur, a new experiment using them is
> planned.

This study is sometimes cited as an excuse to put off installation of
transponders until inexpensive mode S transponders are available. My
take on it is that it addressed a fairly narrow concern, the possible
inability of ATC to properly discern a group of thermalling mode C
equipped gliders. It did not examine whether airborne collision
avoidance systems would continue to provide warnings when confronted by
such situations.

The times when I've been surprised by the close approach of larger
aircraft have been while cruising between thermals, when I'm generally
alone or at a fair distance from other gliders. While thermalling, I
have a view of pretty much the entire sky, and I have a much better
chance of seeing approaching traffic in plenty of time to avoid it.

Marc

[Swiftel]

:-) bugger - I thought they land vertically...??

by the way - when I flew in "black forest gliding site"
in Colorado 1980, it was possible to fly with the glider
on top over the incoming traffic to the mountains and
higher than a certain minimum height stright over the
airport. Is that still possible in the US in times of new
home security or is it now forbidden and are you will
be shot down and then imprisioned under Ashcrofts
creation, the patriot act?
Chris

"Eric Greenwell" > wrote in message
...
> CH wrote:
> > and how long does the battery last?
> > with the transponder on?
>
> Aye, and that's the rub: they come down to the airport, don't they? And
> the airport airspace doesn't go all the way up to 18000 here in the USA,
> but only to about 10,000 or so. And the buggers don't drop down into the
> top, but slide in from the side. Can you believe it?
>
> change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
> USA
>

[Eric Greenwell]

Marc Ramsey wrote:
> Robert Ehrlich wrote:
>
>> An experiment in the french Alps made with a group of tow planes
>> mimicking glider flight, i.e. circling together from time to time has
>> shown that transponders, except in mode S, may not be very useful in
>> gliders. As soon as 2 or more gliders are close together, e.g. circling
>> in the same thermal of working together the same ridge, they are hit
>> simultaneaously by the radar beam and generate simultaneaously their
>> responses, which results in both interfering and nothing useful
>> received at ATC. I had the chance of having one of the engineers
>> involved in the experiment as a passenger last September and he confirmed
>> this. In mode S, as each transponder is specifically adressable,
>> this mess will probably not occur, a new experiment using them is
>> planned.
>
>
> This study is sometimes cited as an excuse to put off installation of
> transponders until inexpensive mode S transponders are available. My
> take on it is that it addressed a fairly narrow concern, the possible
> inability of ATC to properly discern a group of thermalling mode C
> equipped gliders. It did not examine whether airborne collision
> avoidance systems would continue to provide warnings when confronted by
> such situations.

Surely this situation occurs at Minden regularly. Does Reno ATC have
trouble "losing" gliders when they thermal together? Or are they still
aware that something is located there, even if Mode C info is lost? And
even if it is a problem, doesn't ATC still much prefer gliders to have a
transponder than not?

I'd expect at least ONE good signal to be received every 5-15 seconds,
as the gliders' positions change and one antenna is in a much better
position the other ones.

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

Eric Greenwell
Washington State
USA

[Eric Greenwell]

Chris Nicholas wrote:

> Mil80c > , another point you need to be
> aware of;
>
> Many gliders, e.g. mine (a Ka6E), have neither panel space for a
> transponder nor capability of carrying any more weight for the extra
> batteries - I am already on max AUW, on a CofA which has already been
> extended as far as it can be - I am 208 pounds with a parachute, and
> there are plenty of heavier pilots than that.
>
> If a new generation of lightweight, low power transponders emerges (the
> UK CAA has persuaded one manufacturer to build a prototype which tested
> OK), and if ICAO accept 20 w output instead of 100+, and if the thing is
> taken to commercial production, and if it can come with an option of a
> small remote control panel I could strap to my knee, with the larger
> piece and battery going into the stowage behind the pilot's seat, and if
> I can lose enought weight to compensate for it, then it might be viable.

Transponder + encoder = 1 kg
7 amphour battery = 2.3 kg
ant and cable = .4 kg
mounting all of it = .5 kg
TOTAL = 4.2 kg or 9.3 pounds

If this is what is keeping you from installing a transponder that you
think you need, I suggest you take another look at your priorities. Put
in the transponder by - losing 10 pounds; getting a lighter parachute;
removing something from the panel; flying 10 pounds overgross and cut
your critical speeds a couple of knots. Or, if you want to spend about
$600-700 more, get the Filser Mode S when it's available and shave off a
couple pounds using a smaller battery and no external encoder.
--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Chris Nicholas]

Eric, my point was - and remains - that package and weight are issues
which should not be overlooked.

Most of your suggestions are not acceptable - my panel is full of things
I want, I have about as light a parachute as I know of, and flying
outside the max AUW is a no-no for insurance, CofA, and club rules
purposes. Those might not feature in your priority list, but they do
for a lot of other people. Saying I could lose weight is not very
relevant - probably most of us could - but at the margin there must be
some people for whom another 9 pounds is a diet too far.

Of course, I could go and spend 20k, 40k, or 60k on a bigger glider as
well as the several thousand k on a Mode S transponder etc.. If it were
the only way to fly, I would have to look at that. Until it is
mandatory, for many people (not just me, the original enquirer wanted to
know the general issues AIUI) that would not be an option.

And in priority lists, avoiding being killed has several other dangers
more prevalent than collision with airliners, judging by the accident
statistics.

I am not one of those determined never to use transponders. As it
happens, I can see the day coming when I will want one for my sort of
flying in the place I do it, and I will have to solve the
cost/package/weight issues then - but we are not yet there. I hope the
technology then available will make it easier - but I am not holding my
breath, as I said.

Regards - Chris N.

[Ben Flewett]

There are lots of excellent reasons for not requiring
gliders to carry transponders but this study seems
flimsy. In NZ we often have groups of gliders flying
together whilst using transponders - no problem.

The main reasons for not requiring gliders to carry
transponders are:

- if airspace is managed well they are not required
in most areas. The real problem is that the groups
that draw the lines on the maps give the commercial
airlines more airspace than is required. For example,
Auckland (NZ) airport has more airspace around it than
Heathrow.

- as a glider pilot I don’t want to spend my day listening
to commercial pilots talking to ATC all day. I prefer
to have the radio tuned to a gliding frequency or off.

- most (but not all) controllers don’t understand how
gliders operate. The glider pilot is often required
to provide training to controllers whilst trying to
fly their glider. I don’t like having to do this…
“no, I am a glider which means I have no engine and
thus I cannot maintain 3000ft”.

- most glider pilots (including me) are not commercial
pilots and are not practiced at talking to ATC. Controllers
are used to speaking to commercial pilots and often
become frustrated with amateur glider pilots. The
also become frustrated with the unpredictable flight
path of gliders.

Once you agree to put transponders in gliders you are
obliged to use them and they are a pain in the ass.
If you only give commercial operators the airspace
they need there should be plenty left over for gliders.



At 18:36 22 January 2004, Marc Ramsey wrote:
>Robert Ehrlich wrote:
>> An experiment in the french Alps made with a group
>>of tow planes
>> mimicking glider flight, i.e. circling together from
>>time to time has
>> shown that transponders, except in mode S, may not
>>be very useful in
>> gliders. As soon as 2 or more gliders are close together,
>>e.g. circling
>> in the same thermal of working together the same ridge,
>>they are hit
>> simultaneaously by the radar beam and generate simultaneaously
>>their
>> responses, which results in both interfering and nothing
>>useful
>> received at ATC. I had the chance of having one of
>>the engineers
>> involved in the experiment as a passenger last September
>>and he confirmed
>> this. In mode S, as each transponder is specifically
>>adressable,
>> this mess will probably not occur, a new experiment
>>using them is
>> planned.
>
>This study is sometimes cited as an excuse to put off
>installation of
>transponders until inexpensive mode S transponders
>are available. My
>take on it is that it addressed a fairly narrow concern,
>the possible
>inability of ATC to properly discern a group of thermalling
>mode C
>equipped gliders. It did not examine whether airborne
>collision
>avoidance systems would continue to provide warnings
>when confronted by
>such situations.
>
>The times when I've been surprised by the close approach
>of larger
>aircraft have been while cruising between thermals,
>when I'm generally
>alone or at a fair distance from other gliders. While
>thermalling, I
>have a view of pretty much the entire sky, and I have
>a much better
>chance of seeing approaching traffic in plenty of time
>to avoid it.
>
>Marc
>

[Kirk Stant]

Ben Flewett > wrote in message >...
> There are lots of excellent reasons for not requiring
> gliders to carry transponders but this study seems
> flimsy. In NZ we often have groups of gliders flying
> together whilst using transponders - no problem.

As I see it (and this is for the Western US, and may not apply in NZ
or the UK, etc) there are really only two reasons for not carrying a
transponder: No place to put it in the glider (I've been trying to
figure out where to install one in my LS6 (small panel), it will take
a complete redo of the panel to squeeze it in; and cost - as soon as I
win the lottery (or get REALLY scared by an airliner) I will probably
get one.
>
> The main reasons for not requiring gliders to carry
> transponders are:
>
> - if airspace is managed well they are not required
> in most areas. The real problem is that the groups
> that draw the lines on the maps give the commercial
> airlines more airspace than is required. For example,
> Auckland (NZ) airport has more airspace around it than
> Heathrow.

If you fly away from airliners, or airways, then the midair risk is
obviously low. I fly right next to the Phoenix Class B and share
airspace with a lot of traffic. I'm still in Class E, so a
transponder isn't required and I'm not talking to ATC, but still it
would be nice to be "seen" by any TCAS-equipped planes in the
vicinity, especially when cruising (i.e. invisible) at high altitude
(cloudbase above 18000' is not uncommon out here).

> - as a glider pilot I don?t want to spend my day listening
> to commercial pilots talking to ATC all day. I prefer
> to have the radio tuned to a gliding frequency or off.

Same here, and since I'm VFR in Class E airspace, the only time I talk
to ATC is when I think it may help - like during the week near a busy
military base. Then I let them know where I am, and the controllers
have always been very receptive - vectoring the fighters around me if
necessary. Having a transponder would make it easier for ATC to track
me, and many fighters could see me as well with their systems. It
doesn't mean I would have to talk to them more. Is it different in
NZ? (aside from no fighters - a shame about your A-4s and MB-339s!)

> - most (but not all) controllers don?t understand how
> gliders operate. The glider pilot is often required
> to provide training to controllers whilst trying to
> fly their glider. I don?t like having to do this?
> ?no, I am a glider which means I have no engine and
> thus I cannot maintain 3000ft?.

Again, just having a transponder doesn't mean you have to talk to ATC
if VFR, it means ATC will see you and know you are VFR (squawking
1200) and let other traffic know you are there. If you do decide to
talk to ATC, it's that much easier for them to locate you. And the
ATC controller is not controlling you, so it isn't your concern if he
doesn't understand gliders - it's his, since his responsibility it to
protect the airplanes that he is "controlling"; those on IFR
flightplans in his airspace. Trust me, he will appreciate any
"training" you can give him! (thinks - invite local ATC for a glider
ride - many of them are pilots anyway and would jump at the chance!).

> - most glider pilots (including me) are not commercial
> pilots and are not practiced at talking to ATC. Controllers
> are used to speaking to commercial pilots and often
> become frustrated with amateur glider pilots. The
> also become frustrated with the unpredictable flight
> path of gliders.

C'mon, if stinkpot student Cezzna pilots can do it, even glider
guiders can learn to speak ATC! Try it, if you step on your johnson
you can always give your buddy's identification and turn off the
radio! And at the speeds we go, to ATC we aren't unpredictable, we
are parked!

> Once you agree to put transponders in gliders you are
> obliged to use them and they are a pain in the ass.
> If you only give commercial operators the airspace
> they need there should be plenty left over for gliders.

How are they a pain in the ass? Put in the extra battery, turn it on
when you takeoff, turn it off when you land, take out and charge the
extra battery. Again, this may only apply to the US, but having a
transponder doesn't mean you have to talk to ATC. It means that when
you do want ATC to know where you are, they will see you, and that
some airplanes (those equipped with TCAS or similar systems) will have
a much better chance of seeing and avoiding you. If you fly (location
or altitude) where there is little commercial, business, or military
traffic, a transponder will probably not help much, since most small
planes don't have a TCAS-like capability.

Just like most safety issues, the is a cost and risk tradeoff. Some
day (unfortunately, probably due to a bad glider-airliner midair),
transponders will probably be mandated, probably within certain
altitudes (say, above 10,000ft within 50 miles of Class B and C, for
example, with no exceptions). When that happens, we will have to
solve the problem.

Cheers,

Kirk

[Eric Greenwell]

Kirk Stant wrote:

> As I see it (and this is for the Western US, and may not apply in NZ
> or the UK, etc) there are really only two reasons for not carrying a
> transponder: No place to put it in the glider (I've been trying to
> figure out where to install one in my LS6 (small panel), it will take
> a complete redo of the panel to squeeze it in; and cost - as soon as I
> win the lottery (or get REALLY scared by an airliner) I will probably
> get one.

Kirk makes some good points. Let me suggest one way to talk yourself
(not Kirk specifically, but pilots in general) past the hurdle of cost :
think of it as "insurance", and compare it to the cost of insuring your
glider. For a lot of people, it's $900+, which is about half the cost of
a transponder installation. When I look at it that way, I'm buying many
years of "insurance" for a one-time fee that is two years of hull insurance.


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Eric Greenwell
Washington State
USA

[Eric Greenwell]

Chris Nicholas wrote:

> Eric, my point was - and remains - that package and weight are issues
> which should not be overlooked.

True, especially if it involves a battery, the majority of the weight in
the installation. It must be properly installed and accounted for in the
W&B. The rest of the items aren't a problem.

snip

> And in priority lists, avoiding being killed has several other dangers
> more prevalent than collision with airliners, judging by the accident
> statistics.

Part of the reason is a lot of pilots in high risk areas use
transponders. We'll never know how many collisions are avoided because
of this, of course. Your situation sounds like it isn't in a high risk area.

>
> I am not one of those determined never to use transponders. As it
> happens, I can see the day coming when I will want one for my sort of
> flying in the place I do it, and I will have to solve the
> cost/package/weight issues then - but we are not yet there. I hope the
> technology then available will make it easier - but I am not holding my
> breath, as I said.

The glacial pace of change is disappointing. It took a _long_ time for
the small Microair and Becker transponders to actually hit the shelves,
and the Filser has been a mirage for even longer. It looks like it will
actually be available this year! So, something so very different, like a
low power portable unit you can stick to the canopy with a suction cup,
is likely years away.

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Eric Greenwell
Washington State
USA

[Bob Kuykendall]

Earlier, Ben Flewett > wrote:

> ...Once you agree to put transponders
> in gliders you are obliged to use them
> and they are a pain in the ass...

If that's on the basis of your personal experience, I'd be inclined to
check if maybe you mounted the antenna the wrong way up. :)

Where I fly, there are airliners. We have a letter of agreement that
allows us one squawk code. No talking to Center; it's just set and
forget. And, yes, there are officially rules about always using the
transponder if it is available. Uh huh. Right.

Bob K.

[Bob Korves]

In the Reno, Nevada USA area we have an assigned transponder frequency for
gliders, 0440. We generally leave our transponder squawking this code and
then stay on the glider frequency unless our location is close to the main
arrival/departure paths to Reno or if entering the class C is immanent. The
approach controllers don't really want to talk to us and are happy to just
know where we are and how high. The TCAS units in the airliners provide the
same information for them. We in gliders try to keep our eyes looking
outside, and it mostly all seems to work pretty well. I have had no close
airline encounters with an operating transponder aboard, versus several very
close encounters without one.
-Bob Korves
5K LAK-17a
5H DuoDiscus

"Ben Flewett" > wrote in message
...
> There are lots of excellent reasons for not requiring
> gliders to carry transponders but this study seems
> flimsy. In NZ we often have groups of gliders flying
> together whilst using transponders - no problem.
>
> The main reasons for not requiring gliders to carry
> transponders are:
>
> - if airspace is managed well they are not required
> in most areas. The real problem is that the groups
> that draw the lines on the maps give the commercial
> airlines more airspace than is required. For example,
> Auckland (NZ) airport has more airspace around it than
> Heathrow.
>
> - as a glider pilot I don't want to spend my day listening
> to commercial pilots talking to ATC all day. I prefer
> to have the radio tuned to a gliding frequency or off.
>
> - most (but not all) controllers don't understand how
> gliders operate. The glider pilot is often required
> to provide training to controllers whilst trying to
> fly their glider. I don't like having to do this.
> "no, I am a glider which means I have no engine and
> thus I cannot maintain 3000ft".
>
> - most glider pilots (including me) are not commercial
> pilots and are not practiced at talking to ATC. Controllers
> are used to speaking to commercial pilots and often
> become frustrated with amateur glider pilots. The
> also become frustrated with the unpredictable flight
> path of gliders.
>
> Once you agree to put transponders in gliders you are
> obliged to use them and they are a pain in the ass.
> If you only give commercial operators the airspace
> they need there should be plenty left over for gliders.
>
>
>
> At 18:36 22 January 2004, Marc Ramsey wrote:
> >Robert Ehrlich wrote:
> >> An experiment in the french Alps made with a group
> >>of tow planes
> >> mimicking glider flight, i.e. circling together from
> >>time to time has
> >> shown that transponders, except in mode S, may not
> >>be very useful in
> >> gliders. As soon as 2 or more gliders are close together,
> >>e.g. circling
> >> in the same thermal of working together the same ridge,
> >>they are hit
> >> simultaneaously by the radar beam and generate simultaneaously
> >>their
> >> responses, which results in both interfering and nothing
> >>useful
> >> received at ATC. I had the chance of having one of
> >>the engineers
> >> involved in the experiment as a passenger last September
> >>and he confirmed
> >> this. In mode S, as each transponder is specifically
> >>adressable,
> >> this mess will probably not occur, a new experiment
> >>using them is
> >> planned.
> >
> >This study is sometimes cited as an excuse to put off
> >installation of
> >transponders until inexpensive mode S transponders
> >are available. My
> >take on it is that it addressed a fairly narrow concern,
> >the possible
> >inability of ATC to properly discern a group of thermalling
> >mode C
> >equipped gliders. It did not examine whether airborne
> >collision
> >avoidance systems would continue to provide warnings
> >when confronted by
> >such situations.
> >
> >The times when I've been surprised by the close approach
> >of larger
> >aircraft have been while cruising between thermals,
> >when I'm generally
> >alone or at a fair distance from other gliders. While
> >thermalling, I
> >have a view of pretty much the entire sky, and I have
> >a much better
> >chance of seeing approaching traffic in plenty of time
> >to avoid it.
> >
> >Marc
> >
>
>
>

[Robert Ehrlich]

Marc Ramsey wrote:
>
> ... It did not examine whether airborne collision
> avoidance systems would continue to provide warnings when confronted by
> such situations.
> ...

The only such system I have heard about is TCAS. As far as I know
this system is not available on gliders, only on big airplanes
carrying passengers or military ones. It should emit hints to the
pilot for avoiding the collision based on altitude information, assuming
that the other aircraft is going to fly at a constant altitude, or
to follow the hint of its own TCAS, and neither is true for a glider.

[Marc Ramsey]

Robert Ehrlich wrote:
> The only such system I have heard about is TCAS. As far as I know
> this system is not available on gliders, only on big airplanes
> carrying passengers or military ones. It should emit hints to the
> pilot for avoiding the collision based on altitude information, assuming
> that the other aircraft is going to fly at a constant altitude, or
> to follow the hint of its own TCAS, and neither is true for a glider.

TCAS/ACAS detects nearby transponder equipped aircraft. In the US and
western Europe, almost all aircraft larger than small twins now have
them. They will provide useful warning of the presence of a nearby mode
C equipped glider, whether or not the glider is flying straight and level.

Marc

[F1y1n]

....
> whether or not the glider is flying straight and level.

No.

Besides, exactly how many gliders are flying with Mode C right now?
Maybe one 1-26 in North Dakota?

[Eric Greenwell]

F1y1n wrote:
> ....
>
>>whether or not the glider is flying straight and level.
>
>
> No.
>
> Besides, exactly how many gliders are flying with Mode C right now?
> Maybe one 1-26 in North Dakota?

In the USA, hundreds, at least, but mostly in the southwest and eastern
parts of the country. Stick your nose into the cockpits at Minden, for
starters. Once the Microair and Becker became available, they were
flying off the shelves at Wings & Wheels, Knauff & Grove, and elsewhere.
Motorgliders are much more likely to have them, also. In our ASH 26 E
owners group, I think about half of the 30 owners have Mode C.

By the time the 1-26 in North Dakota has one, the rest of us will have
moved onto Mode S.

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Eric Greenwell
Washington State
USA

[CH]

my experience is, that ATCs do not like glider pilots
as soon as they find out, that you cannot keep your
flight level.
In central Europe I had a transponder in the glider,
to get permission to cross some controlled corridors.
I mostly got permission to cross the airspace with
the condition of keeping flight level! A reply of not
being able to keep flight level invertet mostly the
permission into refusal.
The trick was then to enter the airspace first and then
request for sinking to flightlevel (-2FL for the 20km).
But the ATC never liked you for doing that!!

I think Transponder requirement is only virtually
increasing safety. You accept to install transponders
and as a thank you, they will steal you some more
airspace which has been free for VFR before!

Chris


"Mil80C" > wrote in message
...
> Thanks all for your responses, the idea was posted in another NG and as I
am
> not of the soaring fraternaty, could not speak against it with any
> experience. I will say that as an ATC, I will allways support your sport.
>
> "Ramy Yanetz" > wrote in message
> om...
> > $30 will get you an extra battery which will run your transponder longer
> > than you can stay in the air. Unfortunately many pilots as well as the
FAA
> > don't know this.
> > Ramy
> >
> > "CH" > wrote in message
> > ...
> > > and how long does the battery last?
> > > with the transponder on?
> > > Australia decided, that planes without a permanent source
> > > of power on board, do not need transponders in mixed
> > > airspace.
> > > I would prefer, that IFR traffic out of airport airspace should
> > > fly higher than the convection height from sunrise to sunset :-)
> > > How's that??
> > > Chris

[CH]

my experience is, that ATCs do not like glider pilots
as soon as they find out, that you cannot keep your
flight level.
In central Europe I had a transponder in the glider,
to get permission to cross some controlled corridors.
I mostly got permission to cross the airspace with
the condition of keeping flight level! A reply of not
being able to keep flight level invertet mostly the
permission into refusal.
The trick was then to enter the airspace first and then
request for sinking to flightlevel (-2FL for the 20km).
But the ATC never liked you for doing that!!

I think Transponder requirement is only virtually
increasing safety. You accept to install transponders
and as a thank you, they will steal you some more
airspace which has been free for VFR before!

Chris


"Robert Ehrlich" > wrote in message
...
> Chris Nicholas wrote:
> An experiment in the french Alps made with a group of tow planes
> mimicking glider flight, i.e. circling together from time to time has
> shown that transponders, except in mode S, may not be very useful in
> gliders. As soon as 2 or more gliders are close together, e.g. circling
> in the same thermal of working together the same ridge, they are hit
> simultaneaously by the radar beam and generate simultaneaously their
> responses, which results in both interfering and nothing useful
> received at ATC. I had the chance of having one of the engineers
> involved in the experiment as a passenger last September and he confirmed
> this. In mode S, as each transponder is specifically adressable,
> this mess will probably not occur, a new experiment using them is
> planned.

[Duane Eisenbeiss]

"Eric Greenwell" > wrote in message
...
> Kirk Stant wrote:
>
For a lot of people, it's $900+, which is about half the cost of
> a transponder installation. When I look at it that way, I'm buying many
> years of "insurance" for a one-time fee that is two years of hull
insurance.
>
Your "cost" seems a little low for the "total cost" of a transponder,
encoder, extra battery, and installation. Also, your
"one-time fee " should include the cost of recertification every 24 months
which could be around $200. That might be between 10% to 30% of the annual
hull insurance (depending on hull value).

Duane

[Mike Borgelt]

On Fri, 23 Jan 2004 19:32:14 GMT, Marc Ramsey >
wrote:

>Robert Ehrlich wrote:
>> The only such system I have heard about is TCAS. As far as I know
>> this system is not available on gliders, only on big airplanes
>> carrying passengers or military ones. It should emit hints to the
>> pilot for avoiding the collision based on altitude information, assuming
>> that the other aircraft is going to fly at a constant altitude, or
>> to follow the hint of its own TCAS, and neither is true for a glider.
>
>TCAS/ACAS detects nearby transponder equipped aircraft. In the US and
>western Europe, almost all aircraft larger than small twins now have
>them. They will provide useful warning of the presence of a nearby mode
>C equipped glider, whether or not the glider is flying straight and level.
>
>Marc


go to www.arinc.com and search for TCAS. You will find a very useful
paper describing the characteristics of the TCAS system.

After describing how wonderful it all is note the sudden disclaimer at
the end.

Mike Borgelt

[Mark James Boyd]

Robert Ehrlich > wrote:
>Marc Ramsey wrote:
>>
>> ... It did not examine whether airborne collision
>> avoidance systems would continue to provide warnings when confronted by
>> such situations.
>> ...
>
>The only such system I have heard about is TCAS. As far as I know
>this system is not available on gliders, only on big airplanes
>carrying passengers or military ones. It should emit hints to the

I've seen a $20,000 version of TCAS, with a graphic display and
altitude displayed, in an acquantence's 182. It seemed a little
big for a glider (display the size of a Garmin 430). And
my goodness I can only imagine the power consumption!

[Eric Greenwell]

Duane Eisenbeiss wrote:
> "Eric Greenwell" > wrote in message
> ...
>
>>Kirk Stant wrote:
>>
>
> For a lot of people, it's $900+, which is about half the cost of
>
>>a transponder installation. When I look at it that way, I'm buying many
>>years of "insurance" for a one-time fee that is two years of hull
>
> insurance.
>
> Your "cost" seems a little low for the "total cost" of a transponder,
> encoder, extra battery, and installation.

It will be larger if you have to install another battery and pay someone
to do the total installation, but a lot of people will be able to use
the battery they have and do the installation themselves (proper
signoffs required, of course). A Microair + encoder + antenna is about
$1800 from your favorite soaring supplier.

> Also, your
> "one-time fee " should include the cost of recertification every 24 months
> which could be around $200. That might be between 10% to 30% of the annual
> hull insurance (depending on hull value).

A VFR check is about $50-$70; IFR certification is much more stringent
and is $150-$300. Hardly anyone will want to fly their glider IFR, but I
know at least one pilot that does (not IMC, but on IFR flight plans).

I decided to install one after seeing too many airliners too close.
Anyone that feels that way about their flying should look into
installing one, because it's not as costly they likely think it is. My
articles in the Febuary and March 2002 Soaring covered things in much
more detail than I can here.

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Eric Greenwell
Washington State
USA

[Eric Greenwell]

Mike Borgelt wrote:

>
> go to www.arinc.com and search for TCAS. You will find a very useful
> paper describing the characteristics of the TCAS system.
>
> After describing how wonderful it all is note the sudden disclaimer at
> the end.

Could you be more specific, like a title? I get 32 hits and the few I
checked don't seem to be it.

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Eric Greenwell
Washington State
USA

[Mark James Boyd]

From what I can gather, the low-power transponders are 400mA
and encoder 200mA at about 12 volts.

The microfilm superthin solar panels about 1 foot square (12" by 12")
advertise 600mA at about 12 volts.

Sadly, the solar panels in my experience don't put out rated power
on typical days, with less than ideal sun angles (maybe really only
putting out 25%).

Also, I suspect transponders underrate their power consumption,
and if flown in high jet traffic areas (where they get
pinged by ATC and the jets), probably consume quite a bit more.

So really one might be looking at 8 square feet of solar
array just for a transponder! Maybe a little hard to
implement on a glider without using the wing surfaces,
and the caveats that entails...

Well, it was a nice thought...

[F.L. Whiteley]

"Mark James Boyd" > wrote in message
news:40140af4$1@darkstar...
> From what I can gather, the low-power transponders are 400mA
> and encoder 200mA at about 12 volts.
>
> The microfilm superthin solar panels about 1 foot square (12" by 12")
> advertise 600mA at about 12 volts.
>
> Sadly, the solar panels in my experience don't put out rated power
> on typical days, with less than ideal sun angles (maybe really only
> putting out 25%).
>
> Also, I suspect transponders underrate their power consumption,
> and if flown in high jet traffic areas (where they get
> pinged by ATC and the jets), probably consume quite a bit more.
>
> So really one might be looking at 8 square feet of solar
> array just for a transponder! Maybe a little hard to
> implement on a glider without using the wing surfaces,
> and the caveats that entails...
>
> Well, it was a nice thought...

That's today, tomorrow may well be different.

http://www.lbl.gov/Science-Articles/Archive/MSD-Alivisatos-solarcells.html

http://www.scienceagogo.com/news/20030814225502data_trunc_sys.shtml

or this

http://www.californiasolarcenter.org/solareclips/2003.01/20030128-6.html

Perhaps someday be able to shoot a top coat that will take care of keeping
the batteries up. There's work being done at the nanotech level to make
these much more efficient. Imagine the diversity of applications, roofing
materials, car finishes, clothing, tents, aircraft, boats, etc.

Frank Whiteley
Colorado

[Eric Greenwell]

The situation isn't nearly so gloomy!

Mark James Boyd wrote:
> From what I can gather, the low-power transponders are 400mA
> and encoder 200mA at about 12 volts.

My Becker and ACK encoder ~ 410 ma with no replies, and less than 500 ma
even in southern California airspace. A 5 hour flight is 2.5 amphour,
leaving lots of juice for the other instruments on the typical 7 ah battery.

>
> The microfilm superthin solar panels about 1 foot square (12" by 12")
> advertise 600mA at about 12 volts.
>
> Sadly, the solar panels in my experience don't put out rated power
> on typical days, with less than ideal sun angles (maybe really only
> putting out 25%).

Put two on! But even one, with your assumption, means the battery has to
supply 1.7 ah to the battery, leaving ~ 5 ah in the battery for other
purposes. With two supplying 300 ma, the net transponder usage is only 1 ah!

>
> Also, I suspect transponders underrate their power consumption,
> and if flown in high jet traffic areas (where they get
> pinged by ATC and the jets), probably consume quite a bit more.

Not true for the Becker. Ask a Microair owner about it's consumption.
>
> So really one might be looking at 8 square feet of solar
> array just for a transponder! Maybe a little hard to
> implement on a glider without using the wing surfaces,
> and the caveats that entails...

The Strobl panels used by the German manufacturers are very efficient
(http://www.strobl-solar.de/ - use the Google translation tools) and can
supply enough with less than 2 square feet. The disadvantage is the
cost, so most people would probably opt for another, or bigger, battery.

>
> Well, it was a nice thought...

It _is_ a nice thought! People are doing it - it works!

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Washington State
USA

[Mike Raisler]

TCAS installed on all transport category aircraft can "read" mode "c" or "s"
and determine if a climb or descent is needed to avoid the other aircraft.
The glider does not need to have TCAS installed, only a transponder, in
order for the other aircafts TCAS system alert for an avoidance manuever.


"Robert Ehrlich" > wrote in message
...
> Marc Ramsey wrote:
> >
> > ... It did not examine whether airborne collision
> > avoidance systems would continue to provide warnings when confronted by
> > such situations.
> > ...
>
> The only such system I have heard about is TCAS. As far as I know
> this system is not available on gliders, only on big airplanes
> carrying passengers or military ones. It should emit hints to the
> pilot for avoiding the collision based on altitude information, assuming
> that the other aircraft is going to fly at a constant altitude, or
> to follow the hint of its own TCAS, and neither is true for a glider.

[Mike Borgelt]

On Sat, 24 Jan 2004 14:57:28 -0800, Eric Greenwell
> wrote:

>Mike Borgelt wrote:
>
>>
>> go to www.arinc.com and search for TCAS. You will find a very useful
>> paper describing the characteristics of the TCAS system.
>>
>> After describing how wonderful it all is note the sudden disclaimer at
>> the end.
>
>Could you be more specific, like a title? I get 32 hits and the few I
>checked don't seem to be it.


Eric,

The file you want is tcas.pdf
It is about 500k. If you can't find it I'll send it to you.

Mike Borgelt

[Eric Greenwell]

Mike Borgelt wrote:
> On Sat, 24 Jan 2004 14:57:28 -0800, Eric Greenwell
> > wrote:
>
>
>>Mike Borgelt wrote:
>>
>>
>>>go to www.arinc.com and search for TCAS. You will find a very useful
>>>paper describing the characteristics of the TCAS system.
>>>
>>>After describing how wonderful it all is note the sudden disclaimer at
>>>the end.
>>
>>Could you be more specific, like a title? I get 32 hits and the few I
>>checked don't seem to be it.
>
>
>
> Eric,
>
> The file you want is tcas.pdf
> It is about 500k. If you can't find it I'll send it to you.

Please send it - I can't find it. Thanks.
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Washington State
USA

[Ben Flewett]

A number of times I have switched on my transponder
and called for a clearance but ATC have not been able
to see me. I can see my transponder being interogated,
I have good battery power, everything seems to be working
but ATC still can't see me. This has happened to a
number of pilots I know.

So next time you set and forget... don't assume your
transponder is actually working.

If you don't call for a clearance you have no idea
whether you are transmitting or not.



At 17:00 23 January 2004, Bob Kuykendall wrote:
>Earlier, Ben Flewett wrote:
>
>> ...Once you agree to put transponders
>> in gliders you are obliged to use them
>> and they are a pain in the ass...
>
>If that's on the basis of your personal experience,
>I'd be inclined to
>check if maybe you mounted the antenna the wrong way
>up. :)
>
>Where I fly, there are airliners. We have a letter
>of agreement that
>allows us one squawk code. No talking to Center; it's
>just set and
>forget. And, yes, there are officially rules about
>always using the
>transponder if it is available. Uh huh. Right.
>
>Bob K.
>

[Ben Flewett]

Kirk,

We use transponders in a very different way in NZ.
I consider them a pain in the ass but many NZ pilots
would disagree. This is a very big generalisation
but... the pilots that don't mind using transponders
are more focused on flying rather than soaring... if
you know what I mean.

However, as I mentioned in an earlier posting... If
you don't call for a clearance there is a chance your
transponder is not transmitting correctly despite what
it may be telling you. If I am flying in the same
airspace as commercial jets I want to know for sure
that ATC can see me.

For me the single biggest risk to our sport is the
possiblity of a commercial airliner being brought down
by a glider. If this happens gliding will loose -
it will not matter who is at fault.

Ben.



At 15:30 23 January 2004, Kirk Stant wrote:
>Ben Flewett wrote in message news:...
>> There are lots of excellent reasons for not requiring
>> gliders to carry transponders but this study seems
>> flimsy. In NZ we often have groups of gliders flying
>> together whilst using transponders - no problem.
>
>As I see it (and this is for the Western US, and may
>not apply in NZ
>or the UK, etc) there are really only two reasons for
>not carrying a
>transponder: No place to put it in the glider (I've
>been trying to
>figure out where to install one in my LS6 (small panel),
>it will take
>a complete redo of the panel to squeeze it in; and
>cost - as soon as I
>win the lottery (or get REALLY scared by an airliner)
>I will probably
>get one.
>>
>> The main reasons for not requiring gliders to carry
>> transponders are:
>>
>> - if airspace is managed well they are not required
>> in most areas. The real problem is that the groups
>> that draw the lines on the maps give the commercial
>> airlines more airspace than is required. For example,
>> Auckland (NZ) airport has more airspace around it
>>than
>> Heathrow.
>
>If you fly away from airliners, or airways, then the
>midair risk is
>obviously low. I fly right next to the Phoenix Class
>B and share
>airspace with a lot of traffic. I'm still in Class
>E, so a
>transponder isn't required and I'm not talking to ATC,
>but still it
>would be nice to be 'seen' by any TCAS-equipped planes
>in the
>vicinity, especially when cruising (i.e. invisible)
>at high altitude
>(cloudbase above 18000' is not uncommon out here).
>
>> - as a glider pilot I don?t want to spend my day listening
>> to commercial pilots talking to ATC all day. I prefer
>> to have the radio tuned to a gliding frequency or
>>off.
>
>Same here, and since I'm VFR in Class E airspace, the
>only time I talk
>to ATC is when I think it may help - like during the
>week near a busy
>military base. Then I let them know where I am, and
>the controllers
>have always been very receptive - vectoring the fighters
>around me if
>necessary. Having a transponder would make it easier
>for ATC to track
>me, and many fighters could see me as well with their
>systems. It
>doesn't mean I would have to talk to them more. Is
>it different in
>NZ? (aside from no fighters - a shame about your A-4s
>and MB-339s!)
>
>> - most (but not all) controllers don?t understand
>>how
>> gliders operate. The glider pilot is often required
>> to provide training to controllers whilst trying to
>> fly their glider. I don?t like having to do this?
>> ?no, I am a glider which means I have no engine and
>> thus I cannot maintain 3000ft?.
>
>Again, just having a transponder doesn't mean you have
>to talk to ATC
>if VFR, it means ATC will see you and know you are
>VFR (squawking
>1200) and let other traffic know you are there. If
>you do decide to
>talk to ATC, it's that much easier for them to locate
>you. And the
>ATC controller is not controlling you, so it isn't
>your concern if he
>doesn't understand gliders - it's his, since his responsibility
>it to
>protect the airplanes that he is 'controlling'; those
>on IFR
>flightplans in his airspace. Trust me, he will appreciate
>any
>'training' you can give him! (thinks - invite local
>ATC for a glider
>ride - many of them are pilots anyway and would jump
>at the chance!).
>
>> - most glider pilots (including me) are not commercial
>> pilots and are not practiced at talking to ATC. Controllers
>> are used to speaking to commercial pilots and often
>> become frustrated with amateur glider pilots. The
>> also become frustrated with the unpredictable flight
>> path of gliders.
>
>C'mon, if stinkpot student Cezzna pilots can do it,
>even glider
>guiders can learn to speak ATC! Try it, if you step
>on your johnson
>you can always give your buddy's identification and
>turn off the
>radio! And at the speeds we go, to ATC we aren't unpredictable,
>we
>are parked!
>
>> Once you agree to put transponders in gliders you
>>are
>> obliged to use them and they are a pain in the ass.
>> If you only give commercial operators the airspace
>> they need there should be plenty left over for gliders.
>
>How are they a pain in the ass? Put in the extra battery,
>turn it on
>when you takeoff, turn it off when you land, take out
>and charge the
>extra battery. Again, this may only apply to the US,
>but having a
>transponder doesn't mean you have to talk to ATC.
>It means that when
>you do want ATC to know where you are, they will see
>you, and that
>some airplanes (those equipped with TCAS or similar
>systems) will have
>a much better chance of seeing and avoiding you. If
>you fly (location
>or altitude) where there is little commercial, business,
>or military
>traffic, a transponder will probably not help much,
>since most small
>planes don't have a TCAS-like capability.
>
>Just like most safety issues, the is a cost and risk
>tradeoff. Some
>day (unfortunately, probably due to a bad glider-airliner
>midair),
>transponders will probably be mandated, probably within
>certain
>altitudes (say, above 10,000ft within 50 miles of Class
>B and C, for
>example, with no exceptions). When that happens, we
>will have to
>solve the problem.
>
>Cheers,
>
>Kirk
>

[Eric Greenwell]

Ben Flewett wrote:

> A number of times I have switched on my transponder
> and called for a clearance but ATC have not been able
> to see me. I can see my transponder being interogated,
> I have good battery power, everything seems to be working
> but ATC still can't see me. This has happened to a
> number of pilots I know.

Checking ocasionally is a good idea. In the US, you don't have to ask
for a clearance to determine this, but just contact the local tower or
approach guys and ask if they can see you. Actually getting the system
checked as required every 24 months is also a good idea.
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Washington State
USA

[Mark James Boyd]

Ben Flewett > wrote:
>A number of times I have switched on my transponder
>and called for a clearance but ATC have not been able
>to see me. I can see my transponder being interogated,
>I have good battery power, everything seems to be working
>but ATC still can't see me. This has happened to a
>number of pilots I know.
>
>If you don't call for a clearance you have no idea
>whether you are transmitting or not.

Man, if I had a nickel for every time ATC said they didn't have
me but the airliner 10 miles out had me plain as
day, I'd have some nickels!

Too low, in line with another transponder, receiver too
far away, etc. If I let an ATC guy convince me to swap out
a $1000+ part, I'd get his avionics repair certificate number
first... ;(

[Ian Forbes]

Ben Flewett wrote:

> A number of times I have switched on my transponder
> and called for a clearance but ATC have not been able
> to see me. I can see my transponder being interogated,
> I have good battery power, everything seems to be working
> but ATC still can't see me. This has happened to a
> number of pilots I know.

Their have been similar cases to this in our club. It turns out that ATC
at Cape Town International had set their radar to filter out anything
moving slower than 40kt (ground speed). This I believe to filter out
stationery aircraft on the ground taxiing etc.

Gliders in wave simply disappeared off the radar screens, which did not
help anybody ...


Ian

[Eric Greenwell]

Ian Forbes wrote:
> Ben Flewett wrote:
>
>
>>A number of times I have switched on my transponder
>>and called for a clearance but ATC have not been able
>>to see me. I can see my transponder being interogated,
>>I have good battery power, everything seems to be working
>>but ATC still can't see me. This has happened to a
>>number of pilots I know.
>
>
> Their have been similar cases to this in our club. It turns out that ATC
> at Cape Town International had set their radar to filter out anything
> moving slower than 40kt (ground speed). This I believe to filter out
> stationery aircraft on the ground taxiing etc.
>
> Gliders in wave simply disappeared off the radar screens, which did not
> help anybody ...

Did the gliders have Mode C?

Is the radar for Cape Town just for the airport, or is it intended to
cover a much larger area?

In our area airport radar and the higher altitude radars are separate,
so even if the airport radar folks blanked slow moving traffic, Center
radar would see it.

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Washington State
USA

[Robert Ehrlich]

Mike Raisler wrote:
>
> TCAS installed on all transport category aircraft can "read" mode "c" or "s"
> and determine if a climb or descent is needed to avoid the other aircraft.
> The glider does not need to have TCAS installed, only a transponder, in
> order for the other aircafts TCAS system alert for an avoidance manuever.
>

Ok, but the advice emitted by the TCAS in the other aircraft is based on the
assumption that the glider will keep its flying level and this is not true.

[Marc Ramsey]

"Robert Ehrlich" > wrote:
> Mike Raisler wrote:
> >
> > TCAS installed on all transport category aircraft can "read" mode "c" or
"s"
> > and determine if a climb or descent is needed to avoid the other
aircraft.
> > The glider does not need to have TCAS installed, only a transponder, in
> > order for the other aircafts TCAS system alert for an avoidance
manuever.
> >
>
> Ok, but the advice emitted by the TCAS in the other aircraft is based on
the
> assumption that the glider will keep its flying level and this is not
true.

It is far better than no warning at all. The pilots of the TCAS equipped
aircraft will at least get their heads out of the cockpit and take a look
out of the windows.

Marc

[Eric Greenwell]

Robert Ehrlich wrote:

>>TCAS installed on all transport category aircraft can "read" mode "c" or "s"
>>and determine if a climb or descent is needed to avoid the other aircraft.
>>The glider does not need to have TCAS installed, only a transponder, in
>>order for the other aircafts TCAS system alert for an avoidance manuever.
>>
>
>
> Ok, but the advice emitted by the TCAS in the other aircraft is based on the
> assumption that the glider will keep its flying level and this is not true.

It's my understanding that the conflict resolution algorithm is based on
much more realistic assumptions, so that climbing and turning flight of
the potential threats is included. The simple assumption of straight
flight might have been used in the very beginning, but no longer. If you
have a recent reference that suggests otherwise, I'd like to know about it.

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USA

[Fredrik Thörnell]

Eric Greenwell > skrev den Tue, 03 Feb 2004
12:15:57 -0800:
> It's my understanding that the conflict resolution algorithm is based on
> much more realistic assumptions, so that climbing and turning flight of
> the potential threats is included. The simple assumption of straight
> flight might have been used in the very beginning, but no longer. If you
> have a recent reference that suggests otherwise, I'd like to know about
> it.

The algorithm is to look at a number of consecutive returns to determine a
rate of closure and then divide the distance with this rate to give a
'tau' value, of time to impact should there be a collision. When this
value goes below an [altitude dependant] threshold, you have a traffic
advisory. Another lower [also altitude dependant] threshold, and the TCAS
begins working on a resolution advisory.

In other words, more or less straight but not level flight is assumed.

Cheers,
Fred

[Eric Greenwell]

Fredrik Thörnell wrote:
> Eric Greenwell > skrev den Tue, 03 Feb 2004
> 12:15:57 -0800:
>
>> It's my understanding that the conflict resolution algorithm is based
>> on much more realistic assumptions, so that climbing and turning
>> flight of the potential threats is included. The simple assumption of
>> straight flight might have been used in the very beginning, but no
>> longer. If you have a recent reference that suggests otherwise, I'd
>> like to know about it.
>
>
> The algorithm is to look at a number of consecutive returns to determine
> a rate of closure and then divide the distance with this rate to give a
> 'tau' value, of time to impact should there be a collision. When this
> value goes below an [altitude dependant] threshold, you have a traffic
> advisory. Another lower [also altitude dependant] threshold, and the
> TCAS begins working on a resolution advisory.

After looking at an "Introduction to TCAS II version 7" more closely, I
have to agree that Fred's description is a good one. It says (page 7):

"In particular, it is
dependent on the accuracy of the threat
aircraft's reported altitude and on the
expectation that the threat aircraft will not
make an abrupt maneuver that defeats the
TCAS RA."

I'm guessing the relatively slow speeds (compared to the airliner) and
low G turns of a glider (compared to a fighter, for example) would still
allow the TCAS to sort things out to the benefit of all concerned. At
the least, the TCAS is providing range, bearing, and altitude to the
glider, a big improvement over a pair of eyeballs looking out a window
going 300 knots.

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Washington State
USA

[Robert Ehrlich]

Eric Greenwell wrote:
> ...
> I'm guessing the relatively slow speeds (compared to the airliner) and
> low G turns of a glider (compared to a fighter, for example) would still
> allow the TCAS to sort things out to the benefit of all concerned. At
> the least, the TCAS is providing bearing, and altitude to the
> glider, a big improvement over a pair of eyeballs looking out a window
> going 300 knots.
>

I understand clearly how the TCAS can determine range and altitude (by
timing the return and decoding the encoded altitude), but how can it
determine the bearing? directional antennas coupled with compass information?

[Fredrik Thörnell]

Robert Ehrlich > skrev den Wed, 04 Feb 2004
18:21:08 +0000:

> I understand clearly how the TCAS can determine range and altitude (by
> timing the return and decoding the encoded altitude), but how can it
> determine the bearing? directional antennas coupled with compass
> information?

Directional receiving antenna was correct, compass information was not.
You con't care about the bearing, only the direction. Which won't be too
exact anyway. ;)

Cheers,
Fred

[Eric Greenwell]

Robert Ehrlich wrote:

> Eric Greenwell wrote:
>
>>...
>>I'm guessing the relatively slow speeds (compared to the airliner) and
>>low G turns of a glider (compared to a fighter, for example) would still
>>allow the TCAS to sort things out to the benefit of all concerned. At
>>the least, the TCAS is providing bearing, and altitude to the
>>glider, a big improvement over a pair of eyeballs looking out a window
>>going 300 knots.

>
> I understand clearly how the TCAS can determine range and altitude (by
> timing the return and decoding the encoded altitude), but how can it
> determine the bearing? directional antennas coupled with compass information?

I'm not sure, either. Here's a quote from "Introduction to TCAS II
version 7":

"TCAS interrogates
ICAO-compliant transponders of all aircraft
in the vicinity and based on the replies
received, tracks the slant range, altitude
(when it is included in the reply message),
and bearing of surrounding traffic."

It also uses the term "relative bearing" about half the time, so it's
not clear to me which they mean. I suspect it's actually relative
bearing. In any case, the bearing info appears to be determined by using
two or more antennas.
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Washington State
USA

[Robert Ehrlich]

Eric Greenwell wrote:
> ...
> In any case, the bearing info appears to be determined by using
> two or more antennas.
> ...

More than 2 are necessary. With 2 antennas, you can only measure
the time difference between the 2 received signals. This time
difference can be translated into a distance difference. The points from
where a given difference is observed are on an hyperbola, which
can be considered as the same as its 2 asymptotes, as the distance
to the antennas is high compared to their mutual distance. But
to determine which of the both asymptotes is the correct one, you
need some more information, i.e. another antenna.

[Eric Greenwell]

Robert Ehrlich wrote:

> Eric Greenwell wrote:
>
>>...
>>In any case, the bearing info appears to be determined by using
>>two or more antennas.
>>...
>
>
> More than 2 are necessary. With 2 antennas, you can only measure
> the time difference between the 2 received signals. This time
> difference can be translated into a distance difference. The points from
> where a given difference is observed are on an hyperbola, which
> can be considered as the same as its 2 asymptotes, as the distance
> to the antennas is high compared to their mutual distance. But
> to determine which of the both asymptotes is the correct one, you
> need some more information, i.e. another antenna.

A more careful reading of the document shows only two antennas are used:
one bottom mounted omni-directional and one top mounted directional. It
also shows the omni-directional antenna can optionally be a directional
antenna.

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USA

[Mark James Boyd]

In article >,
Robert Ehrlich > wrote:
>Eric Greenwell wrote:
>> ...
>> In any case, the bearing info appears to be determined by using
>> two or more antennas.
>> ...
>
>More than 2 are necessary. With 2 antennas, you can only measure
>the time difference between the 2 received signals. This time
>difference can be translated into a distance difference. The points from
>where a given difference is observed are on an hyperbola, which
>can be considered as the same as its 2 asymptotes, as the distance
>to the antennas is high compared to their mutual distance. But
>to determine which of the both asymptotes is the correct one, you
>need some more information, i.e. another antenna.

Well, the mode C height information makes this 2 points, and
if you turn the aircraft a few degrees, and assume the points are
(relatively) stationary, you can distinguish between the two points,
right?

The mode C is surely there, but the second part seems
complex. They must do it some other way...

[bumper]

If you are talking about how azimuth is determined by TCAS units, I believe
it is done through the use of a segmented directional receive antenna.
Direction info does not need to be precise within a few degrees.

bumper

"Mark James Boyd" > wrote in message
news:40289d41@darkstar...
> In article >,
> Robert Ehrlich > wrote:
> >Eric Greenwell wrote:
> >> ...
> >> In any case, the bearing info appears to be determined by using
> >> two or more antennas.
> >> ...
> >
> >More than 2 are necessary. With 2 antennas, you can only measure
> >the time difference between the 2 received signals. This time
> >difference can be translated into a distance difference. The points from
> >where a given difference is observed are on an hyperbola, which
> >can be considered as the same as its 2 asymptotes, as the distance
> >to the antennas is high compared to their mutual distance. But
> >to determine which of the both asymptotes is the correct one, you
> >need some more information, i.e. another antenna.
>
> Well, the mode C height information makes this 2 points, and
> if you turn the aircraft a few degrees, and assume the points are
> (relatively) stationary, you can distinguish between the two points,
> right?
>
> The mode C is surely there, but the second part seems
> complex. They must do it some other way...

[Calergin]

I hope you dont mind some info here. I happen to have a little experience
with TCAS and how it works.

TCAS only uses slant range (distance from own ship to target) and the
reported mode C (or mode S but that is another story) altitiude. From this
it creates a TAU value, as stated earlier, which is the range over range
rate. When the time to closest approach thresholds are broken depending on
own ships altitiude and state (ie gear down) than alerts and or resolution
advisories are issued.

TCAS is a very complicated system that was carefully designed and test
extensively by the FAA. It has several inches of documents to describe in
gross detail how it is to work. I have just way simplified what it does.


TCAS II antennas are 4 element and are capable of determining bearing and
doing directional interrogations. The bearing accuracy is not good enough
for alerting so bearing is only used on the cockpit display. This is for
the aid to see and avoid part of TCAS. A lot of $$ was spent on trying to
make a system that allowed turns to avoid collisions. It is prefered not to
have pilots deviate their altitude. Without the up and comming GPS addition
to the system there was no way to make a cost effective system with the
needed bearing accuracy. The up and comming ADSB systems will change cost
and accuracy of availible systems.

Bearing is determined by either the difference in phase or amplitude of the
received signal depending on manufacturer. It was their choice what they
used as long as they passed the tests. Either system works very good. I
believe almost all TCAS II systems are installed with a directional antenna
top and bottom.

One big issue for the TCAS is the fact that a large population of aircraft
owners are not maintaining their Mode C encoders and having them check every
2 years. Encoders have been found to be off by as much as 1000 or more
feet. If you are flying at 1500 feet and your encoder says you are at 2200
feet and the TCAS equipt aircraft is at 2000 feet guess who will be
decending to avoid a target at 2200 feet. Guess who will be in for a big
surprise if they get to 1500 feet.

I hope that helps.


"bumper" > wrote in message
...
> If you are talking about how azimuth is determined by TCAS units, I
believe
> it is done through the use of a segmented directional receive antenna.
> Direction info does not need to be precise within a few degrees.
>
> bumper
>
> "Mark James Boyd" > wrote in message
> news:40289d41@darkstar...
> > In article >,
> > Robert Ehrlich > wrote:
> > >Eric Greenwell wrote:
> > >> ...
> > >> In any case, the bearing info appears to be determined by using
> > >> two or more antennas.
> > >> ...
> > >
> > >More than 2 are necessary. With 2 antennas, you can only measure
> > >the time difference between the 2 received signals. This time
> > >difference can be translated into a distance difference. The points
from
> > >where a given difference is observed are on an hyperbola, which
> > >can be considered as the same as its 2 asymptotes, as the distance
> > >to the antennas is high compared to their mutual distance. But
> > >to determine which of the both asymptotes is the correct one, you
> > >need some more information, i.e. another antenna.
> >
> > Well, the mode C height information makes this 2 points, and
> > if you turn the aircraft a few degrees, and assume the points are
> > (relatively) stationary, you can distinguish between the two points,
> > right?
> >
> > The mode C is surely there, but the second part seems
> > complex. They must do it some other way...
>
>

[Mike Borgelt]

On Tue, 10 Feb 2004 19:27:31 -0500, "Calergin" >
wrote:

>I hope you dont mind some info here. I happen to have a little experience
>with TCAS and how it works.

snip
>
>One big issue for the TCAS is the fact that a large population of aircraft
>owners are not maintaining their Mode C encoders and having them check every
>2 years. Encoders have been found to be off by as much as 1000 or more
>feet. If you are flying at 1500 feet and your encoder says you are at 2200
>feet and the TCAS equipt aircraft is at 2000 feet guess who will be
>decending to avoid a target at 2200 feet. Guess who will be in for a big
>surprise if they get to 1500 feet.
>
>I hope that helps.
If you go to http://www.arinc.com/tcas/ and download
Introduction to TCAS II 7.0 you will have a good grasp of TCAS
priciples of operation.

Mike Borgelt

[Robert Ehrlich]

Calergin wrote:
> ...
> TCAS only uses slant range (distance from own ship to target) and the
> reported mode C (or mode S but that is another story) altitiude. From this
> it creates a TAU value, as stated earlier, which is the range over range
> rate. When the time to closest approach thresholds are broken depending on
> own ships altitiude and state (ie gear down) than alerts and or resolution
> advisories are issued.
> ...

Can you confirm that such a method for resolution advisories may be of little
help when the conflicting aircraft is a glider unable to maintain its altitude
which will rather seem to vary randomly seen from the TCAS equipped aircraft?