In the UK we are not allowed to fly Gliders in Class
A or Airways, full stop, period! We can sometimes access
Class B and Class D with an ATC clearance by radio.
The vast majority of gliding is done in Glass G airspace
where we are largely segregated from commercial air
traffic. However the latter are increasingly starting
to use the Class G around the smaller regional airports,
which is probably why the CAA wants the compulsory
fitting of Mode S transponders. The other issue is
the use of the open airspace by UAVs (mostly by the
US Military as far as I can find out). There is no
mandatory requirement for fitting airband radios at
the moment, so I don't expect to get any improved access
to controlled airspace by fitting transponders.

In the US the fitting of transponders appears to be
voluntary, if the owners/pilots consider it necessary
in their local airspace. If the CAA gets its way, Mode
S will be compulsory for all aircraft in the UK, including
low value vintage machine that only occasionally fly,
and even when they do stay local to the airfield. Basically
these beautiful machines will probably have to be placed
in museums or scrapped, which in my opinion would be
a great shame. We currently have a thriving vintage
glider movement in the UK.

The UK is a damp little island with far too much cloud,
often with a very low base. To successfully fly cross-country
you really do need all the glide performance you can
get.

Mode S transponders can only give collision warnings
to ACAS/TCAS equipped aircraft, or via radio messages
from radar equipped ATC. They are virtually useless
for preventing collisions between gliders or GA aircraft.
If we have to fit anything, I would prefer to wait
for ADS-B or some development of FLARM, which is of
general use to all pilots. Transponders are crude,
old fashioned, WW2 technology!

Derek Copeland


At 15:24 05 September 2006, Eric Greenwell wrote:
W.J. (Bill) Dean (U.K.). wrote:

After two or three days, with his ship not going as
well compared with the others as he expected, he removed
it. The
difference was immediate and obvious, he described
to me the difference with
it fitted as turning the ASW27 into an ASW20! Remember,
he had been flying
with the antenna for some time, it was only in contest
against other similar
gliders with good pilots that he saw the difference.

I remain skeptical: I sure didn't see any difference
at all when I
fitted a transponder antenna to my ASH 26 E, flying
against gliders I'd
flown with for years, nor have I heard of anyone else
noticing a
difference. Perhaps something unusual was occurring
in his case.

Please do not talk as if flying in UK contests involves
the same collision
risk with CAT as flying in the high skies around Minden
(I have never done
that, alas!).

I won't, and I didn't. My remarks were directed at
a Std Cirrus pilot
who felt he needed every crumb of performance, and
that was why he
wouldn't consider a transponder. My belief the drag
increase is
insgnificant, so it shouldn't be a factor in his decision.
The need for
it and the cost are the most important factors, I think.


To anyone buying a new modern machine from Schleicher,
Schempp or the
others, the cost of fitting a transponder is only
a small percentage of the
total cost, but would still involve finding panel
space, and sufficient
power (particularly if the transponder is to be on
whenever airborne). But
there are still a lot of low value gliders in use
in the UK, and a lot of
gliding being done where the actual collision risk
where a transponder would
make a difference is very small.

Also the situation in much of the USA. Though, I don't
think the value
of the glider should be a factor in the decision to
install a
transponder. I realize you are using the glider value
as a proxy for the
spare cash the owner has, but I'd rather the focus
was on the collision
risk, the value of reducing it, and the cost of installing
a transponder.

In the USA, I wonder how many of the 1-26 fleet are
fitted?

I don't know, but some do have them in the Minden area.

Are you allowed to fly in airways in the UK (as we
do in the US), and
would having a transponder give you greater access
to them?

--
Note: email address new as of 9/4/2006
Change 'netto' to 'net' to email me directly

Eric Greenwell - Washington State, USA

'Transponders in Sailplanes' on the Soaring Safety
Foundation website
www.soaringsafety.org/prevention/articles.html

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