Transponders

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

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 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.

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

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.


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

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.

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

Eric Greenwell
Washington State
USA

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...

"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/...olarcells.html

http://www.scienceagogo.com/news/200...runc_sys.shtml

or this

http://www.californiasolarcenter.org...0030128-6.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

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!

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

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