Feds Want to Equipe Gliders With Transponders and Radios

On Apr 28, 9:32*am, Larry Dighera wrote:
On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps
wrote in
:

A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

That's a constructive suggestion. *

How large must such a radar reflector be? *

It's a retroreflector, I have one in the form of a tube about 3 inches
in diameter and 2 feet long. The corner cubes are inside that. I have
no idea how effective it is compared to a classic reflector which
occupies *a cube about 1 foot across and retroreflects the radar
equally in all directions.
...

Interesting. *Thanks for the information. *

How do you think it might affect a sailplane's L/D?


Well, if the sailplane skin is transparent to radar a big reflector
could be mounted inside, they don't weigh much. On the other hand a
cylinder type reflector could be made quite aerodynamic and even
incorporated into (say) the wing tips?

Cheers

On Sun, 27 Apr 2008 15:03:33 -0700 (PDT), WingFlaps
wrote in
:

On Apr 28, 9:32*am, Larry Dighera wrote:
On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps
wrote in
:

A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

That's a constructive suggestion. *

How large must such a radar reflector be? *

It's a retroreflector, I have one in the form of a tube about 3 inches
in diameter and 2 feet long. The corner cubes are inside that. I have
no idea how effective it is compared to a classic reflector which
occupies *a cube about 1 foot across and retroreflects the radar
equally in all directions.
...

Interesting. *Thanks for the information. *

How do you think it might affect a sailplane's L/D?


Well, if the sailplane skin is transparent to radar a big reflector
could be mounted inside, they don't weigh much. On the other hand a
cylinder type reflector could be made quite aerodynamic and even
incorporated into (say) the wing tips?

Cheers

That sounds like a very simple, inexpensive and effective solution to
the issue. Best of all, the pilot can't turn it off. :-)

On Sun, 27 Apr 2008 10:09:57 -0700 (PDT), Andrew Sarangan
wrote:

On Apr 27, 12:01 pm, "Vaughn Simon"
wrote:
"Larry Dighera" wrote in message

...



If this is implemented, will it affect powered aircraft without
electrical systems too?

Almost certainly



How much does the gliders right-of-way over powered aircraft affect
this issue?

Not at all. Any glider pilots who depends on powered aircraft to see them
and to automatically get out of their way has a death wish.

Right-of-way rules have two uses:
1) Provides a framework of preplanned manuvers for aircraft to use to avoid
each other (but only if they both see each other, know the regulations, and are
inclined to follow them).

And now the big one: (2) It provides lawers and bureaucrats with a
methodology for assigning blame after an accident.



Is ATC going to take legal and financial responsibility for separation
if gliders are mandated to be so equipped and operated?

No more than they do now.



Is the big-sky-theory a myth?

It always has been a myth.


No it is not a myth. If you evenly spread the number of GA aircraft
below 12,000 ft across the U.S all traveling at random directions, the
probability of collision will be extremely low enough to be considered
zero. The problem is that the big sky theory does not apply near
terminal airspace where the airplanes are not traveling in random
directions and altitudes.

The spirit of the original transponder exemption was to allow for
older airplanes that were manufactured before the days electrical
avionics became commonplace. So I can see the justification for this
proposal. However, a full blown mode C transponder may not be
necessary. A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

***********************************

Does ATC use skin paint any more????

Big John

Big John wrote:

However, a full blown mode C transponder may not be
necessary. A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

Not really. More like a corner reflector. Take three mutually
perpendicular reflecting planes and you get an interesting and useful
property -- an incoming beam from any direction gets reflected three times
and ends up going out in exactly the same direction it came from. Exactly
what you want to give an artificially large radar profile.

See here for an example:

http://www.landfallnavigation.com/sd152.html

In any case, primary radar (even with the help of a passive, if efficient,
reflector on the target) only gives you bearing and range. To get
altitude, you need Mode C.

On Sun, 27 Apr 2008 22:17:44 -0400, Roy Smith wrote in
:

Big John wrote:

However, a full blown mode C transponder may not be
necessary. A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

Not really. More like a corner reflector. Take three mutually
perpendicular reflecting planes and you get an interesting and useful
property -- an incoming beam from any direction gets reflected three times
and ends up going out in exactly the same direction it came from. Exactly
what you want to give an artificially large radar profile.

See here for an example:

http://www.landfallnavigation.com/sd152.html


Hey. That looks like just the ticket, and the price is right. Of
course, once it's STCed ...

Here's the corner reflector definition in Federal Standard 1037C:
http://www.its.bldrdoc.gov/fs-1037/dir-009/_1298.htm
Photo: http://www.its.bldrdoc.gov/fs-1037/images/coriverc.gif
That doesn't look nearly as useful as the example you provided.

In any case, primary radar (even with the help of a passive, if efficient,
reflector on the target) only gives you bearing and range. To get
altitude, you need Mode C.

I've had ATC call traffic "altitude unknown" often. I don't see the
lack of altitude information as a real limitation, but then I'm
neither a controller nor engineer.

So while the NTSB in Safety Recommendation A-08-10 through -13 dated
March 31, 2008 is recommending removing the glider transponder
exemption:

The Board notes that, because of the limitations of the
see-and-avoid concept, transponder-initiated collision alerts
(either from ATC or TCAS) provide both VFR and IFR aircraft with a
higher degree of safety in an environment where highspeed closure
rates are possible. Therefore, the Safety Board further concludes
that transponders are critical to alerting pilots and controllers
to the presence of nearby traffic, so that collisions can be
avoided, and that gliders should not be exempt from the
transponder requirements. This is especially important at higher
altitudes, where flight crews may rely more on their TCAS,
expecting that other aircraft, including light aircraft, are in
contact with ATC and/or are transponder-equipped.

Therefore, the Safety Board believes that the FAA should remove
the glider exemptions from the FARs that pertain to transponder
requirements and use.

It would seem that the language the NTSB used leaves room for
equipping gliders with a simple passive corner reflector installed
within the composite or other non-metallic skin of the glider, thus
overcoming the lack of electrical system, and providing ATC with a
useable target for potential traffic conflicts.

Larry Dighera wrote:

...
Interesting. Thanks for the information.

How do you think it might affect a sailplane's L/D?

Well, if the sailplane skin is transparent to radar a big reflector
could be mounted inside, they don't weigh much. On the other hand a
cylinder type reflector could be made quite aerodynamic and even
incorporated into (say) the wing tips?

Cheers

That sounds like a very simple, inexpensive and effective solution to
the issue. Best of all, the pilot can't turn it off. :-)

Locally, approach radar has no trouble finding our transponderless
gliders (when we call them), tracking them, and warning/diverting other
traffic. We generally do this within 15-20 miles of our towered
airports. It works well for us, given the altitudes we fly at.

I don't know that a corner reflector would improve on the situation, or
if they would detect the gliders without the radio call. While the pilot
can't turn it off, it may be the controller doesn't notice it without
the radio call, and may not be able to see it because of other clutter,
or perhaps the display filter settings.

It's worth contacting ATC in your area to see if they are willing and
able to do the same for you. It's not practical everywhere, but it's
cheap and easy if it is.

A problem the reflector can not solve is TCAS will still not detect the
glider. This might be deal-breaker for the FAA/NTSB people.

--
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

Larry.. DO you fly gliders?
From these statements it would appear that you do not.
Gliders may or may not have electrical systems, they do not "generate
power", but stored battery power of a limited life span.
Gliders are small, batteries are small, everything needs to be small.

NTSB "recommends", FAA cannot mandate without a comment period and a change
to many CFRs.
Technology is coming for the small transponder, along with ATS-B. Why would
I put a 50# $15K ATS-B system in a $15K glider.
Small transponders now are about $1300 plus antenna and installation. It can
be done.

My issue is not with TCAS equipped aircraft, but with smaller GA aircraft
that do not have TCAS, do not have a Garmin 430 with TIS (or equivalent) and
are not talking to ATC. It does no good to have a transponder, when the
aircraft causing the traffic conflict is not talking to anyone. Just sitting
there FDH and not even paying attention in the traffic pattern.

Last Saturday we had at least 4 transient aircraft attempt to land at the
airport with 15 to 20 knot tail winds, and against the flow of traffic.
They could not even listen up to the radio to figure out the runway in use,
or even look at a wind sock or a huge flag and see the 15knt winds and make
up their own mind about the landing runway.

What makes you think a transponder in a glider would make any difference.

And local ATC can see my non-transponder equipped glider just fine, when I
am high enough for radar coverage.
It's called raw radar skin paint. And yes, I am looking at the requirements
(Not Govt' requirement but electical and space in the aircraft requirements)
and feasibility for installing transponders in our gliders.

B

"Larry Dighera" wrote in message
...
On Sun, 27 Apr 2008 16:01:31 GMT, "Vaughn Simon"
wrote in
:


"Larry Dighera" wrote in message
. ..

If this is implemented, will it affect powered aircraft without
electrical systems too?

Almost certainly


That's the way I saw it also.

Here are a few pertinent questions:

What are the full implications of installing an electrical system in a
glider?

If implemented, will the requirement for an electrical system kill
low-cost glider training operations?

Would the CAP glider training operations, which typically provide
winch launch and pattern work, be impacted?

What are the full implications of installing an electrical system in a
Champ or Cub? Isn't their performance so marginal already, that they
will become impractical due to increased empty weight and drag, and
power reduction with the addition of an alternator, battery,
communications radio, transponder, antennas, wiring, switches, etc?

Would the work have to be done by an A&P and approved by the FAA for
each aircraft/glider modified?

Will aircraft/glider useful load be affected?


How much does the gliders right-of-way over powered aircraft affect
this issue?

Not at all.


So you don't believe there is any possibility that Part 121 or 135
operator advocate organizations have been lobbying the government to
increase the conspicuity of gliders or to enable their TCAS systems to
warn operators of glider proximity?

What is the possibility of NextGen ATC accommodating non-metallic
aircraft without electrical systems? Without transponders? Without
radio communications?


Any glider pilots who depends on powered aircraft to see them
and to automatically get out of their way has a death wish.


It's difficult to deny that. But it doesn't address the issue of
liability.


Right-of-way rules have two uses:
1) Provides a framework of preplanned manuvers for aircraft to use to
avoid
each other (but only if they both see each other, know the regulations,
and are
inclined to follow them).


Actually, that is true if only one pilot makes visual contact too.


And now the big one: (2) It provides lawers and bureaucrats with a
methodology for assigning blame after an accident.


So Right-of-way regulations provide a basis for aggrieved parties to
seek compensation from regulation violators, and assign responsibility
too.


Is ATC going to take legal and financial responsibility for separation
if gliders are mandated to be so equipped and operated?

No more than they do now.


I would find ATC's responsibility for separating NORDO gliders that
paint no primary target to be nonexistent presently. If this proposal
is enacted, the situation will change.


Is the big-sky-theory a myth?

It always has been a myth.


At the risk of tangential drift, isn't the BST currently employed by
the FAA to separate high-speed military aircraft on VFR low-level
Military Training Routs from civil flights? In light of the mythical
status of the BST, shouldn't that flaw in the NAS be corrected also?


Vaughn


Thank you for your insightful comments.

"Andrew Sarangan" wrote in message
...
On Apr 27, 2:02 pm, Larry Dighera wrote:


I think the FAR can be justifiably modified to only exempt airplanes
originally manufactured with no electrical system, but all airplanes
manufactured since 2008 (or whenever) operating in airspace where a
transponder is required should be equipped with one.


But not all aircraft are required to have a transponder in all categories of
airspace...
Sure.. all AIRPLANES with electrical generating systems should have a
transponder, but not all AIRCRAFT have electrical generating systems. Even
ones built today, sort of a Catch-22.

B

BT wrote:

Small transponders now are about $1300 plus antenna and installation. It can
be done.

That's a great price! Where do you get these? What brand? The ones I
know about (Becker, Microair) are $1900 plus $200 for the encoder.

--
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

On Apr 27, 3:45 pm, Larry Dighera wrote:
On Sun, 27 Apr 2008 15:03:33 -0700 (PDT), WingFlaps
wrote in
:



On Apr 28, 9:32 am, Larry Dighera wrote:
On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps
wrote in
:

A radar reflector like they use on weather balloon ought be
sufficient. It is just a piece of foil with a large cross section.

That's a constructive suggestion.

How large must such a radar reflector be?

It's a retroreflector, I have one in the form of a tube about 3 inches
in diameter and 2 feet long. The corner cubes are inside that. I have
no idea how effective it is compared to a classic reflector which
occupies a cube about 1 foot across and retroreflects the radar
equally in all directions.
...

Interesting. Thanks for the information.

How do you think it might affect a sailplane's L/D?

Well, if the sailplane skin is transparent to radar a big reflector
could be mounted inside, they don't weigh much. On the other hand a
cylinder type reflector could be made quite aerodynamic and even
incorporated into (say) the wing tips?

Cheers

That sounds like a very simple, inexpensive and effective solution to
the issue. Best of all, the pilot can't turn it off. :-)

Unfortunately too simple. The problem is NOT ATC's equipment having
trouble painting a glider. The problem is the threshold of sensitivity
on their radars is set far too high to display us since they
intentionally filter out things as slow as a glider, particularly if
it's thermalling. We are simply filtered out as clutter (according to
the rep Reno sent to address PASCO last winter). That said, I'm sure
we don't all read the same on radar, but gliders are not the stealth
aircraft they are being made out to be. I believe cockpit alone has a
rather large signature, unless of course you paid the extra $1,000,000
for the one molecule thick layer of electrically deposited gold on
your canopy. There's more to a stealth aircraft then it being made of
fiberglass, or even carbon...

Paul