At 11:36 AM 5/07/05 +1000, you wrote:
>
>The danger that concerns me is what happens in the period between two
>sailplanes on a parallel track becoming a collision solution when one of
>them turns. During this period the two fail to see a beacon for say 5-8
>seconds, a lot of ground is covered in this period.
>
This would be taken care of by the nearest mode.i.e. there's a glider out
there in your two o'clock or 10 as the case may be. There are lots of
cases where a collision can build in a very short time. I bet nobody really
thought that two gliders on parallel tracks going in the same direction,
600 meters apart and 250 feet altitude difference could collide easily. 12
seconds from no danger to collision. What's your scan time? Is he in your
field of view? In the Nimbus 2C/ASW22 collision at Horsham a few years ago
it seems a few seconds was all it took.
Apart from lookout and scan there needs to be an understanding of
vulnerability.
There are three problems: colliding with a glider you didn't see in time to
avoid it, colliding with a glider that you know is in the vicinity but one
or both flightpaths change inside your scan time and you then fail to see
in time and colliding with a glider due to misjudgement of separation.
We've had all of the above and FLARM(or any similar system) would likely be
very useful in the first and second cases. I don't see it helping in the
third.
I've had a close, head on encounter and I'd like more than 3 seconds,
please, to do something. We both saw each other and took evasive action.
There seems to be a lot of misinformation and expectation. FLARM is an aid
to VFR see and avoid. Even the highly specified, TSO'd ADSB system is only
expected on Airservices own estimate to prevent 75% of mid airs. That was
based on analysis of mid airs in Oz going back to the 60's.
I posted the url for that a couple of weeks ago here.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
Int'l + 61 429 355784
email: [EMAIL PROTECTED]
website: www.borgeltinstruments.com
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