Transponders

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" 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

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

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.

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 a

- 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

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 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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Eric Greenwell
Washington State
USA

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... ;(

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

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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Eric Greenwell
Washington State
USA