Nearly Mid-Air Collision at Estrella

Do military aircraft utilize transponder signal based
collision avoidance systems?


At 15:18 02 February 2004, Kirk Stant wrote:
(Terry Claussen) wrote in message
news:...
A lousy end to what was a beautiful day of soaring,
thanks to the USMC
and my own lack of vigilance.

Some thoughts on this incident (and comments in subsequent
posts):

If I hear a powerplane (any kind!) while cruising and
don't see him -
My response is to IMMEDIATELY throw up a wing and pull
a hard S-turn.
This does two things: It lets you check behind, where
your greatest
threat is, and throws a much bigger visual target for
the approaching
plane to see. And he is close enough to hear, he will
probably see
you. This works very well for military jets, not so
well for
airliners and bugsmashers, from personal experience.

At the altitudes we usually fly, fighters will usually
be transiting
at relatively low speed (about 300 knots, perhaps 350).
Down low (or
high), they will be going a lot faster (450 - 600 knots)
but if you
are that low you are about to landout! But even at
350 knots, you
have time to hear and react to the sound of the approaching
fighters
(this from personal experience).

Note I say 'fighters' - there will almost always be
at least two of
them, maybe more, so do not stop searching after finding
one figher -
it's the wingman, not the flight lead, that is most
likely to hit you
(because his attention is divided between maintaining
formation and
clearing his flightpath). In the US most fighters
will be either in
relatively close formation (easy to see both) or spread
out 1 to 2
miles line abreast (hard to see both). And it probably
isn't the one
that is closest to hitting you that you are going to
pick up first,
since he will be closest to nose-on. The good news
is that if either
figher sees you, he will warn the other to avoid you.
Fighter pilots
look out the window a lot, it is actually something
they train at all
the time. Don't count on that from airline or lightplane
pilots,
though!

Airliners descending to land are a problem, since you
absolutely
cannot hear them - you have to pick them up (since
they will probably
not maneuver unless they get really exited!). Of course,
they are big
and brightly painted, so are a bit easier to see.

When cruising, obviously it is most dangerous at the
VFR hemispheric
altitudes, but at least you should have an idea where
the threat is
coming from.

Finally, in the US our transition altitude is 18000ft,
and since most
of us use the field elevation to set the altimeter
(instead of calling
FSS), there is going to be some altimeter discrepancies
- so you
really can't count on using altitude for close deconfliction.


Kirk

Gary Evans skrev den 2 Feb 2004
15:32:41 GMT:

Do military aircraft utilize transponder signal based
collision avoidance systems?

Yes, and this does not amuse controllers as they have a fast jet blasting
upwards at umpteen thousand fpm, setting off all the TCAS bells in the
traffic above the sector.

Cheers,
Fred

Fredrik Thörnell wrote in message ...
Gary Evans skrev den 2 Feb 2004
15:32:41 GMT:

Do military aircraft utilize transponder signal based
collision avoidance systems?

Yes, and this does not amuse controllers as they have a fast jet blasting
upwards at umpteen thousand fpm, setting off all the TCAS bells in the
traffic above the sector.

Cheers,
Fred

It depends. The newer, large transport (and tanker?) military
aircraft probably have TCAS, since they are usually equipped to
airliner standards. But they also will almost always be on an IFR
flight plan.

Fighters are a whole different bag of fish: Most have air-to-air
radar that may or may not see a glider (I have seen F-16 radar detect
and lock on to a glider). Some Harriers have a radar, but not all.
Some fighters also have the capability to interrogate a transponder,
much like ATC does; this includes F-15s and some F-16s, not sure about
the radar equipped Harrier 2. In this case, a transponder in the
glider will help a lot. As far as I know, no fighter-type aircraft
have TCAS or similar.

All military aircraft have transponders and are squawking mode 3 and
mode C - but if there are two fighters in formation usually only the
flight lead will be squawking - the wingman will be in STBY as long as
he is part of the formation. So a TCAD or similar device in a glider
may not detect all the threats.

Kirk

Kirk Stant skrev den 2 Feb 2004 11:15:10 -0800:

All military aircraft have transponders and are squawking mode 3 and
mode C - but if there are two fighters in formation usually only the
flight lead will be squawking - the wingman will be in STBY as long as
he is part of the formation. So a TCAD or similar device in a glider
may not detect all the threats.

My mistake. I was reading 'transponder equipped'. And I agree, I have yet
to see TCAS in fighters. No space, no way of effectively fitting it into
the already complicated peacetime cognitive system without reducing the
wartime capability of same.

Thanks for correcting me!

Cheers,
Fred

If radar getting you is a problem, for boats they make fairly
compact aluminum "radar reflectors" that are pretty lightweight.
Dunno if they'd fit in a tail section though, kinda
"ship-in-a-bottle" maybe?

(Mark James Boyd) wrote in message news:401ec338$1@darkstar...
If radar getting you is a problem, for boats they make fairly
compact aluminum "radar reflectors" that are pretty lightweight.
Dunno if they'd fit in a tail section though, kinda
"ship-in-a-bottle" maybe?

I am planning to fit a marine aluminium corner cube into the fuselage
of the Pirat. It's about 12" on each side, very light, and can be
assembled in situ. There more compact reflectors for marine use which
are claimed to have larger radar cross sections, but the emphasis has
to be on "claimed" there.

Active reflectors are also coming in for marine use. They are
not-quite-transponders: when they hear a pulse they send one, or in
some cases several, back. I don't know how compatible they'd be with
airborne radar systems, though.

Ian

On 3 Feb 2004 04:55:56 -0800, (Ian Johnston)
wrote:

(Mark James Boyd) wrote in message news:401ec338$1@darkstar...
If radar getting you is a problem, for boats they make fairly
compact aluminum "radar reflectors" that are pretty lightweight.
Dunno if they'd fit in a tail section though, kinda
"ship-in-a-bottle" maybe?

I am planning to fit a marine aluminium corner cube into the fuselage
of the Pirat. It's about 12" on each side, very light, and can be
assembled in situ. There more compact reflectors for marine use which
are claimed to have larger radar cross sections, but the emphasis has
to be on "claimed" there.

Sounds interesting. Can you supply more detail yet, like cost, weight,
sources?



--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

we have no problems with local ATC radar picking up our Grob 103, LS-4,
Libelle, and of course.. the Schweitzer Iron, 2-33 and 1-26

but they have to be looking at Primary Radar.. and not just the transponders
BT

"Martin Gregorie" wrote in message
...
On 3 Feb 2004 04:55:56 -0800, (Ian Johnston)
wrote:

(Mark James Boyd) wrote in message
news:401ec338$1@darkstar...
If radar getting you is a problem, for boats they make fairly
compact aluminum "radar reflectors" that are pretty lightweight.
Dunno if they'd fit in a tail section though, kinda
"ship-in-a-bottle" maybe?

I am planning to fit a marine aluminium corner cube into the fuselage
of the Pirat. It's about 12" on each side, very light, and can be
assembled in situ. There more compact reflectors for marine use which
are claimed to have larger radar cross sections, but the emphasis has
to be on "claimed" there.

Sounds interesting. Can you supply more detail yet, like cost, weight,
sources?



--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

On Tue, 3 Feb 2004 16:36:06 UTC, Martin Gregorie
wrote:

: On 3 Feb 2004 04:55:56 -0800, (Ian Johnston)
: wrote:

: I am planning to fit a marine aluminium corner cube into the fuselage
: of the Pirat. It's about 12" on each side, very light, and can be
: assembled in situ. There more compact reflectors for marine use which
: are claimed to have larger radar cross sections, but the emphasis has
: to be on "claimed" there.
:
: Sounds interesting. Can you supply more detail yet, like cost, weight,
: sources?

Any chandler will sell them. I'm not sure who does mail order these
days, as a coupleof big names went bust. Gaelforce in Inverness,
maybe, or Jimmy Green in Devon?

I think they are about thirty quid and the one I have on the boat
weighs less than a pound.

Ian

Ian Johnston skrev den 3 Feb 2004 04:55:56 -0800:

I am planning to fit a marine aluminium corner cube into the fuselage
of the Pirat. It's about 12" on each side, very light, and can be
assembled in situ. There more compact reflectors for marine use which
are claimed to have larger radar cross sections, but the emphasis has
to be on "claimed" there.

It'd be interesting to find out what the speed threshold for the doppler
radars typically is. Unfortunately, that is not a piece of information
they go out of their way to make available. The question is, above or
below the speed of a glider in a thermal?

Cheers,
Fred