Many transponders in close proximity

With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

5Z wrote:
With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

5Z wrote:
With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

This was a concern many mango seasons ago when ATC finally had computer
generated Alpha/numerics assigned to traffic they were displaying. ATC
has a number of filter limits which can be adjusted at the controller's
scope.

Billy Hill, Zulu

5Z wrote:
With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,
they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

#2. If multiple gliders (or aircraft) are in the vicinity all
squawking 1200, ATC could not tell one from the other. Mode C (if you
have it) reports altitude, yet if the climb or descent rate is large
(let's say greater than 1500fpm) their equipment typically faults you
off the scope and does not report your altitude. Once again unless you
are given a discrete squawk other than 1200 (VFR traffic).

#3. If multiple gliders (or other aircraft) are in the same proximity
on closing trajectories, the ATC system will issue warnings to the
controller, that he must issue to the offending aircraft, to try to
prevent them from colliding.... Unless you are in direct communication
with ATC, they will probably get extremely miffed (read.. ask you to
call them when you land, and they will probably find you!!) because
they are spending more time trying to cancel these warnings to control
other "participating" aircraft.

#4. MODE S transponders have a discrete ID code embedded in the
transponder that is supposed to be set to your aircraft registry ID
(look on the FAA website for your aircraft registry information and you
will find that ID for your aircraft). Mode S talks to other mode S
equipped transponders, and is typically used to provide TCAS (Traffic
Collision Avoidance System) information to issue the advisories to each
aircraft. If you have this feature, and were to pullup rapidly with
another mode S aircraft overhead, it could set off his traffic warning
system.

#5. I have flown in wave with a transponder equipped glider, yet I was
talking with ATC and had clearance into the window. Always, conditions
were VMC, even though operating in Class A airspace under an IFR Flight
Plan.

#6. Transponders are expensive... DO NOT solve the "see and avoid"
problem.. can potentially really mess ATC up if you are not in direct
contact with them.. and in the case of the Hawker midair..... would not
have prevented the collision.

Jettester (UP)

"jettester" wrote in message
oups.com...
5Z wrote:
With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,
they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

#2. If multiple gliders (or aircraft) are in the vicinity all
squawking 1200, ATC could not tell one from the other. Mode C (if you
have it) reports altitude, yet if the climb or descent rate is large
(let's say greater than 1500fpm) their equipment typically faults you
off the scope and does not report your altitude. Once again unless you
are given a discrete squawk other than 1200 (VFR traffic).

#3. If multiple gliders (or other aircraft) are in the same proximity
on closing trajectories, the ATC system will issue warnings to the
controller, that he must issue to the offending aircraft, to try to
prevent them from colliding.... Unless you are in direct communication
with ATC, they will probably get extremely miffed (read.. ask you to
call them when you land, and they will probably find you!!) because
they are spending more time trying to cancel these warnings to control
other "participating" aircraft.

#4. MODE S transponders have a discrete ID code embedded in the
transponder that is supposed to be set to your aircraft registry ID
(look on the FAA website for your aircraft registry information and you
will find that ID for your aircraft). Mode S talks to other mode S
equipped transponders, and is typically used to provide TCAS (Traffic
Collision Avoidance System) information to issue the advisories to each
aircraft. If you have this feature, and were to pullup rapidly with
another mode S aircraft overhead, it could set off his traffic warning
system.

#5. I have flown in wave with a transponder equipped glider, yet I was
talking with ATC and had clearance into the window. Always, conditions
were VMC, even though operating in Class A airspace under an IFR Flight
Plan.

#6. Transponders are expensive... DO NOT solve the "see and avoid"
problem.. can potentially really mess ATC up if you are not in direct
contact with them.. and in the case of the Hawker midair..... would not
have prevented the collision.

Jettester (UP)


Thank you.

Al G

Great info. It seems obvious that gliders should have a code different
from the generic 1200 so they can be tracked more efficiently and
separated from other general aviation traffic, but I guess there are
only a handful of places in the US where this is the case. Around the
heavily-trafficked Sky Harbor in Phoenix we mix it with dozens of GA
aircraft on 1200, while in the lightly occupied space further south,
the Tucson Soaring Club have been allocated 0400. Perhaps it's time
for some uniform codes?

Mike



Al wrote:
"jettester" wrote in message
oups.com...
5Z wrote:
With all this discussion going on now, maybe someone with some
knowledge or experience could enlighten us on the consequences of 10 or
more sailplanes in a tight gaglge all squawking the same info. Will
ATC see them all? Or will interference and/or filtering software at
ATC make some or all of them invisible?

Will TCAS be able to make sense of all these close together
transponders?

Remember, the typical application of the transponder is to separate
traffic, so it is very unusual to have two (in our case 5, 10 or even
40) or more within 1,000' of each other. Can furrent technology deal
with that, or will equipping all sailplanes create more problems than
it solves?

Thanks

-Tom

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,
they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

#2. If multiple gliders (or aircraft) are in the vicinity all
squawking 1200, ATC could not tell one from the other. Mode C (if you
have it) reports altitude, yet if the climb or descent rate is large
(let's say greater than 1500fpm) their equipment typically faults you
off the scope and does not report your altitude. Once again unless you
are given a discrete squawk other than 1200 (VFR traffic).

#3. If multiple gliders (or other aircraft) are in the same proximity
on closing trajectories, the ATC system will issue warnings to the
controller, that he must issue to the offending aircraft, to try to
prevent them from colliding.... Unless you are in direct communication
with ATC, they will probably get extremely miffed (read.. ask you to
call them when you land, and they will probably find you!!) because
they are spending more time trying to cancel these warnings to control
other "participating" aircraft.

#4. MODE S transponders have a discrete ID code embedded in the
transponder that is supposed to be set to your aircraft registry ID
(look on the FAA website for your aircraft registry information and you
will find that ID for your aircraft). Mode S talks to other mode S
equipped transponders, and is typically used to provide TCAS (Traffic
Collision Avoidance System) information to issue the advisories to each
aircraft. If you have this feature, and were to pullup rapidly with
another mode S aircraft overhead, it could set off his traffic warning
system.

#5. I have flown in wave with a transponder equipped glider, yet I was
talking with ATC and had clearance into the window. Always, conditions
were VMC, even though operating in Class A airspace under an IFR Flight
Plan.

#6. Transponders are expensive... DO NOT solve the "see and avoid"
problem.. can potentially really mess ATC up if you are not in direct
contact with them.. and in the case of the Hawker midair..... would not
have prevented the collision.

Jettester (UP)


Thank you.

Al G

jettester wrote:
Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

EXCELLENT response! Sounds like the "transponder" option is to get a
Zaon MRX http://www.zaonflight.com/mrx.html It's better if I'm AWARE
of ALL the transponders nearby instead of just trying to become visible
to a few others with limited success.

Did a quick Google search for LED strobes and these are intriguing, but
looks like 1/3 to 1/2 amp drain, so even worse than transponder. But,
it may be possible to rig these to flash less frequently...

-Tom

Thanks for the good info--
but I have a question--see #6 below---
If the ASG29 was squaking the discrete code used in the Minden area, would
the 800XP not have been alerted to the conflict?

--
Hartley Falbaum

"jettester" wrote in message
oups.com...
-Tom

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.


#6. Transponders are expensive... DO NOT solve the "see and avoid"
problem.. can potentially really mess ATC up if you are not in direct
contact with them.. and in the case of the Hawker midair..... would not
have prevented the collision.

Jettester (UP)

Mike the Strike wrote:
Great info. It seems obvious that gliders should have a code different
from the generic 1200 so they can be tracked more efficiently and
separated from other general aviation traffic, but I guess there are
only a handful of places in the US where this is the case. Around the
heavily-trafficked Sky Harbor in Phoenix we mix it with dozens of GA
aircraft on 1200, while in the lightly occupied space further south,
the Tucson Soaring Club have been allocated 0400. Perhaps it's time
for some uniform codes?

Mike

By common agreement between Nevada glider operations and Reno ATC,
local gliders all Sqwawk 0440. It works well and then routinely route
traffic around us.

"jettester" wrote in message
oups.com...
#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,

TCAS can't factor multiple threats?!? Even the lowly Zaon MRX can.

they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

TCAS filtering out "highway ground traffic" ...squawking 1200?

The biggest benefit of transponder is not that people on the ground will see
you -- after all, they are not the ones that are going to hit you. My
transponder is on not as much for the ATC, but for the TCAS/TPAS flying out
there.
--
Yuliy