On Feb 10, 12:22*am, Bruce wrote:
Gary Evans wrote:
On Feb 9, 6:02 am, Gilbert Smith wrote:
"BT" wrote:
Having the "right of way" only works if the other pilot see's you.
He can't "yield" to what he does not see.
"None" wrote in message
....
The rules say that an aircraft towing or re-fueling has the right-of-
way over all other powered aircraft.
Please point out to critics of glider operations that every pilot is
taught this rule before flying solo and that this rule is on the
written test he or she must take before getting a license.
Classing this tragedy as a simple collision between two powered
aircraft ignores the flight profile of the glider tug, which would
have been climbing on full power.

I can tell you from my experience of touring in a low wing single, and
from towing thousands of gliders into the air, that the Cirrus pilot
would have been unaware of the Pawnee until it suddenly rose to fill
his windshield. He may have been maintaining a good look-out, but down
and to one side is easily missed, especially with the terrain as a
background.

Do you include this possibility in your scan of the horizon ?

This is real good insight and makes you realize just how difficult see
and avoid can be. It is too easy to just pass it off as the pilot
wasn't looking.

My non-professional opinion. See and avoid is a lot less reliable than
we fondly imagine.

Cognition is a strange thing - camouflage relies on presenting something
in ways we do not recognise. And then it can hide in plain sight. I
would expect that there is a significant fraction of the power flying
fraternity who have no experience or frame to assess what an aerotow /
or gliding operation works like.

So - Cirrus pilot may have been aware of the gliding operation, but have
had no idea of the flight profiles involved. Many power pilots I have
spoken to automatically think of gliders as "things that will descend" -
therefore the risk if any will come from above. When I ask them how they
expect the glider to get above them in the first place you often see
some basic assumptions moving. We rely on framing to simplify our
environment and make all that input understandable. If something does
not fit, we tend to miss it (camouflage) or mis-represent it.

Even if the Cirrus pilot saw the combination, there are a couple of
things against him recognising the danger it represented:
1] His flying experience would probably not lead him to expect it to be
climbing rapidly. Or to continue away from the airfield. Again his
picture of glide ratio is probably framed by what a high wing loading ,
high drag SEL plane does when the fan quits.
2] Humans are notoriously bad at "oscillating disparity" (motion in
depth). Helicopter and Glider pilots get good at working out how fast
other aircraft / birds / stuff is climbing. Other folk have less incentive.
3] COntrast ratio - Another visual limitation may be that the contrast
ratio between the snow on the mountains and the flat terrain the Cirrus
pilot would have to scan to see the tug combination would probably be
very high. Most people have difficulty accommodating the high variance
in brightness. (Think how long it takes to get your night vision back
after an oncoming car leaves their high beams on too long)

My opinion is that see and be seen has a lot of limitations. While it
must logically remain the primary situational awareness tool, we should
recognise the limitations - you can't rely on the Mk1 eyeball and brain
to always recognise danger when it sees "something" that it may not
recognise, or have time to attend to.

Bruce

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Your basic point that "see-and-be-seen" is inadequate is valid.
Compounding the situation in this case is that neither the tug or
glider sported particularly high visibility paint jobs. IIRC 18L was
tan with brown striping and the 2-32 is dull bare metal with sparse
orange and yellow trim. The 2-32 while not stealthy, can be difficult
to see against terrain.

However, in the Boulder case, the rate of climb would have been low
due to the altitude and the very heavy glider - perhaps less than 400
FPM. Further, the Cirrus was flown by a local pilot who should have
been familiar with the aero tow route and the altitudes to expect tow
traffic.

A possible lesson is that if other traffic is required to yield right
of way, tugs should sport high visibility paint.