Transponder Praise

On July 2 (a day with blue skies, a few scattered CUs and typical east
coast haze) a friend and I were thermalling our ASW-20 and ASW-19
sailplanes at 6,000 feet 3 miles SE of Blairstown, NJ (a clearly
marked glider port some 40 miles from Newark Airport and Teterboro
Airport). My Zaon MRX alerted us to traffic at our altitude 5 miles
away, which then rapidly closed on us. Despite our best efforts over
the next 30 seconds, neither my friend nor I saw anything approaching.
Then suddenly we saw a business jet in a 45-50 degree bank less than a
mile away. Apparently my transponder caused a TA on his TCAS, he
looked outside and saw our wings flashing, and he turned away from the
impending collision.

I realize not everyone flies in a high traffic area like that around
NY and PHL. But especially for my soaring friends who fly the
Governor’s Cup course, I strongly recommend you put a transponder in
your ship. They cost less than a glide computer, and while they won’t
tell you where you are, a transponder might just get you home someday…

-John

Transponders are a good thing.. when the other guy has TCAS or TIS
capability.
I would venture a guess it's 50-50 he never saw you and simply reacted to
the TA commands.
The small GA aircraft without a TIS display will still never see you.
BT


"jcarlyle" wrote in message
...
On July 2 (a day with blue skies, a few scattered CUs and typical east
coast haze) a friend and I were thermalling our ASW-20 and ASW-19
sailplanes at 6,000 feet 3 miles SE of Blairstown, NJ (a clearly
marked glider port some 40 miles from Newark Airport and Teterboro
Airport). My Zaon MRX alerted us to traffic at our altitude 5 miles
away, which then rapidly closed on us. Despite our best efforts over
the next 30 seconds, neither my friend nor I saw anything approaching.
Then suddenly we saw a business jet in a 45-50 degree bank less than a
mile away. Apparently my transponder caused a TA on his TCAS, he
looked outside and saw our wings flashing, and he turned away from the
impending collision.

I realize not everyone flies in a high traffic area like that around
NY and PHL. But especially for my soaring friends who fly the
Governor’s Cup course, I strongly recommend you put a transponder in
your ship. They cost less than a glide computer, and while they won’t
tell you where you are, a transponder might just get you home someday…

-John

On Jul 5, 10:21*am, "BT" wrote:
Transponders are a good thing.. when the other guy has TCAS or TIS
capability.
I would venture a guess it's 50-50 he never saw you and simply reacted to
the TA commands.
The small GA aircraft without a TIS display will still never see you.
BT

"jcarlyle" wrote in message

...
On July 2 (a day with blue skies, a few scattered CUs and typical east
coast haze) a friend and I were thermalling our ASW-20 and ASW-19
sailplanes at 6,000 feet 3 miles SE of Blairstown, NJ (a clearly
marked glider port some 40 miles from Newark Airport and Teterboro
Airport). My Zaon MRX alerted us to traffic at our altitude 5 miles
away, which then rapidly closed on us. Despite our best efforts over
the next 30 seconds, neither my friend nor I saw anything approaching.
Then suddenly we saw a business jet in a 45-50 degree bank less than a
mile away. Apparently my transponder caused a TA on his TCAS, he
looked outside and saw our wings flashing, and he turned away from the
impending collision.

I realize not everyone flies in a high traffic area like that around
NY and PHL. But especially for my soaring friends who fly the
Governor’s Cup course, I strongly recommend you put a transponder in
your ship. They cost less than a glide computer, and while they won’t
tell you where you are, a transponder might just get you home someday…

-John

I hope the real point is that without a transponder you are really are
quite invisible in the system. The GA aircraft has a lot less chance
of avoiding you if you don't have a transponder at all. More and more
GA aircraft are flying with "something", but certainly not TCAS. I
wish numbers were available but look around the airport, certainly the
high performance singles crowd and above seem to have traffic
avoidance toys, including PCAS (e.g Zaon MRX) or more advanced TAS
systems from vendors like Avidyne, or they may have TIS, but that's
getting less interesting nowdays. Or GA aircraft may just be under the
control of ATC or under flight following and get a traffic advisory.
And to counter recent concerns about what ATC does with VFR traffic -
I've had excellent advisories of VFR to VFR traffic when in a
sailplane under flight following (and hear them advisign traffic of
me) - including to unknown VFR (i.e. traffic squawking 1200) and heard
traffic advisories about me to airline traffic when not under flight
following (including Reno approach, before the mid-air).

Darryl

On Jul 5, 10:21*am, "BT" wrote:
Transponders are a good thing.. when the other guy has TCAS or TIS
capability.
I would venture a guess it's 50-50 he never saw you and simply reacted to
the TA commands.
The small GA aircraft without a TIS display will still never see you.
BT

Which is why it's good to fly with both a transponder and a PCAS like
the Zaon MRX. I fly near both SFO and RNO airspace, and while these
aids must be regarded as aids - not substitutes - I find them
invaluable for helping "see and be seen." I know there's a cost
involved, but in the grand scheme of the cost of soaring, it is not a
huge increase when amortized over the life of the units.

As I noted in a PASCO Safety Seminar talk last Fall, one way to reduce
fatalities is to treat serious but non-fatal accidents with the same
respect as if there had been loss of life. Along those lines, what our
reaction (and the FAA's!) would have been if the Minden glider-bizjet
midair two years ago had been with an airliner and if there had been
significant loss of life on the airliner. I suspect our use of
transponders and PCAS would go way up, voluntarily at first and then
mandatorily as the FAA got into the act and took away many of our
privileges. Let's not wait for something of that magnitude - which
could kill soaring as we know it along with hundreds of people - to
take action.

I wrote up that talk "Complacency: What Me Worry?" and have posted it
at

http://www-ee.stanford.edu/~hellman/...2007_talk.html

Martin

Agree to all Darryl..
Sadly my club LS4 is without a transponder

But I have listened to ATC and heard them calling traffic, "altitude unknown
appears to be a glider", so they know we are there.
The problem lies with the smaller GA aircraft ducking in under the edge of
Class B so as to not have to talk to approach control while they zip into
one of the satellite airports.

BT

Last Tuesday, I received a package with my transponder in it. Of
course, the soaring weather looked good on Friday and Saturday,
perhaps Sunday, so the installation would have to wait another week.

Today, as I prepare to take off, my MRX fails to turn on. I launch
anyway.

Our airport is located half way between Colorado Springs and Denver.
Lots of airliners, etc. flying overhead at 9-13K MSL (2-5K AGL).

About 45 minutes after launch, I watch a TED 737 cruise less than 1/4
mile abeam my thermal. Later, as I'm getting the last bit of altitude
about 5 E of COS, a Southwest 737 drives right through the center of
my thermal and 500' below. I think all the virga and OD around were
squeezing gliders and airliners into a fairly small area. After the
Southwest jet flew under me, I called COS approach and stayed in
contact for the next 15 miles. They NEVER saw my primary target
(ASH-26E) even though I was able to provide a very accurate position.

What's interesting is that in both cases, I was thermalling, so
providing about the best possible "target" for a visual observation.

Guess what I'll be doing tomorrow!

-Tom

PS Our club just bought 3 MRX units to put in the club ships in order
to provide more info to the pilots. And yes, we are in contact with
both DEN and COS approach regarding the traffic issues.

At 16:34 05 July 2008, jcarlyle wrote:
My Zaon MRX alerted us to traffic at our altitude 5 miles
away, which then rapidly closed on us. Despite our best
efforts over the next 30 seconds, neither my friend nor
I saw anything approaching.
Then suddenly we saw a business jet in a 45-50 degree
bank less than a mile away. Apparently my transponder
caused a TA on his TCAS, he looked outside and saw our
wings flashing, and he turned away from the impending collision.

Assuming that you are talking nautical miles. If you are alerted
to the aircraft at 5 miles and within 30 seconds he is at 1 mile
then is apparently doing 480 knots (well above the 250 kt limit
below 10,000 msl).
If you don't see him and you know he is at your altitude and
closing at that high of a rate, why not just pull full spoilers and
dive to vacate that altitude as quickly as possible?
Is there a better option available?

On Jul 5, 11:27*pm, Soarin Again wrote:
At 16:34 05 July 2008, jcarlyle wrote:

My Zaon MRX alerted us to traffic at our altitude 5 miles
away, which then rapidly closed on us. Despite our best
efforts over the next 30 seconds, neither my friend nor
I saw anything approaching.
Then suddenly we saw a business jet in a 45-50 degree
bank less than a mile away. Apparently my transponder
caused a TA on his TCAS, he looked outside and saw our
wings flashing, and he turned away from the impending collision.

Assuming that you are talking nautical miles. *If you are alerted
to the aircraft at 5 miles and within 30 seconds he is at 1 mile
then is apparently doing 480 knots (well above the 250 kt limit
below 10,000 msl).
If you don't see him and you know he is at your altitude and
closing at that high of a rate, why not just pull full spoilers and
dive to vacate that altitude as quickly as possible?
Is there a better option available?

The distance measurements with PCAS are approximate and only based on
radiated power from the other aircraft's transponder and can be fooled
as the aircraft change atitudes/altirudes relateive to each other.

With two gliders flying near each other and both thermalling (so that
you are most visible to other traffic) I'd be trying to stay with the
other glider (traffic might see and try to avoid one glider and hit
the other), I'd be focused on scanning for the traffic and not be
shoving the nose over and pulling spoilers unless I could see the
traffic and thought that was a good thign to do. If traffic is
getting close on PCAS and I can't see it I will bank or turn the
glider to have a good look around.


Darryl

Six or seven years ago, I started to fly out of Jean, Nevada fairly
often so I installed a transponder. Jean is just outside the Las Vegas
Class B (8 to 9,000' at 20NM), and under the Mode C Veil which - not
printed on charts - is essentially Class B between 9 and 10,000'
unless you have a transponder or use a negotiated climb window.
One weekday morning, the pilot for the skydiving operation helped me
rig. That evening he helped me put the glider back in the box.
As we were pulling tape, he said: "You have a transponder, don't you?
I heard ATC vectoring aircraft around you." The pilot must actually
talk with control before a jump run to allow several small objects to
drop through the veil.
That confirmed the good idea of installing the transponder and
batteries.
Just installed and certified a transponder in the new flying
machine, too. But this is old technology. When we all have
transponders it will drive ATC crazy with gaggles of proximity alarms
going off. Be better if every aircraft had FLARM.
Jim

JS wrote:

Just installed and certified a transponder in the new flying
machine, too. But this is old technology. When we all have
transponders it will drive ATC crazy with gaggles of proximity alarms
going off.

That can be handled with an assigned code like the 0440 used in Reno for
gliders. The software can be instructed to ignore conflicts between 0440
codes, which, I believe, is what is done in Reno. There may be other
methods they can already use, especially if the glider density is lower
than Reno.

Be better if every aircraft had FLARM.

We will, in 10 to 20 years, but we'll likely call it ADSB. FLARM, as
presently implemented, probably wouldn't appeal to 250+ knot airliners,
because it's range is too small. I think it's better to work for a low
cost, low power, ADSB with modest features like the Mitre unit.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org