On Sun, 02 May 2004 00:19:47 GMT, "Bill Daniels"
wrote:


Yes I do fly in the vast empty skies of the western USA, thank goodness.
However, I'm also a pilot who has survived a mid-air with another glider
while flying in those "empty" skies.

Try to picture this. The little device goes "Beep" and when you look at it,
the 20mm 2-digit LED display says "06" meaning 6 gliders are within one
kilometer. My reaction is to look outside like crazy until I can see all
six. It beeps again and displays 07 meaning that another glider has joined
the gaggle. I look even harder. This uses the "Mark 1 eyeball" to it's
maximum.

Extremely accurate GPS data has nothing to do with this. If the error is
that the 7th glider is really 1.005 Km away instead of 1.000 why would I
care? If a glider joins the gaggle without this device there is a very good
chance I will see him while looking for the others even though the device
does not detect him.

It is not necessary to compute the trajectories of all gliders in the gaggle
to determine those with a collision probability. Those 500 feet above and
below present no danger whatsoever.

Now picture an advanced version. The device still displays "07" but it now
sounds "deedle, deedle, deedle" and an LED at 8 O'clock illuminates meaning
that there is a non-zero probability collision threat at that relative
bearing. The "Mark 1 eyeballs" leap into action and I look over my left
shoulder to see that the other glider will pass clear. Is this a "false
alarm"? Not really. I really wanted to see him if he was that close. I
appreciated the "heads up". The device need only compute probabilities for
those targets near and closing while near the same altitude.

Perhaps the problem is calling this an "Anti-Collision Device" when it is
really a situational awareness aid.

As for battery life, perhaps you noticed the news that a fully IFR equipped
Kestral 17 flown by Gordon Boettger flew 1562 Kilometers in 11:15 from
Minden, Nevada, USA to Steamboat Springs, Colorado. Most of the flight was
in wave above 20,000 feet. Gordon's Kestral was transponder equipped as
well as carrying a lot of other electronics to operate legally in positive
control airspace. Battery capacity didn't seem to be a problem.

The device I'm talking about would weigh less than 200 gms and run on four
AA batteries for 50+ hours. The amount of time spent looking at it will be
fractions of a second and then only when critical information is displayed.

Bill Daniels


"electronically enhanced see and avoid" is what we are really after
here, not a 100% guaranteed collision prevention system.

Nearly all gliders already have a GPS of some sort so part of the
hardware already exists.

For those who insist on greater than once per second updates go to the
Garmin website and look at the new Garmin 16A engine which provides 5
Hz updates. This is however, unnecessary.

As someone said here "the glider you don't see is the one that will
get you".(not necessarily true) An electronic system will help with
this which is why fighters got tail warning radar not long after the
invention of radar itself.

Advocating training or better behaviour by pilots probably won't work.
If it did we'd know by now. The collisions we have are the ones left
AFTER this has already been done. Could some people do better? - yes.

This has been going on for 90 years now. Ask the victims of Manfred
von Richthofen, Billy Bishop, Albert Ball and all the others. Even the
aces got surprised occasionally and survived by luck(Adolph Galland)
or not.

You don't need any display in the cockpit, just a voice.(no panel
space required) Some years ago we owned a Nimbus 3DM and it was
remarkable how often a second pair of eyes would pick up something
that one missed.
The electronic systems like FLARM will provide that second pair of
eyes in single seat gliders.

It isn't necessary to have a 100% system. We already do that with
parachutes and in the military, ejection seats. Neither are 100%
effective.

When the alternative is almost certain death even a 50% mitigator
looks good.

Any National gliding body responsible for regulation could trial such
a system at any given site and then go on to require its use
nationwide.


Mike Borgelt