Andrew,
You wrote:
"I have learned from experience that stall characteristics are very
specific to each airframe. There are only generic similarities across
the same model. Even in the ubiquitous Cessna 172, the stall
characteristics may appear to be consistent during an imminent stall,
but if you push it deeper into a stall, or an uncoordinated stall, the
characteristics are not at all similar. On an experimental
construction, I would expect these variations to be more drastic than
in production models.
As soon as I heard about this accident, I looked at the google
satellite map of Livermore airport and wondered why he was tempted to
make a 180. If the golf course had people in it that might be one
reason, but it looks like there are quite a few cow pastures slightly
left of course, and some shallow lakes (reservoirs?) further left."
Yes, that's why I limited my comments to only those aircraft in which I had
actually
performed the various turning stalls. And I explicitly stated that none
of them had laminar flow airfoil sections. Those aircraft which I had tested
where simple, basic and very well behaved in most situations. (Don't secondary
stall an older C-150 with the landing light in the wing unless you have lots
of altitude. It snaps to an instant spin.) Even the simplest and nicest have
a nasty stall in a slipping turn. Laminar flow sections can be notorious in
their stall characteristics. That is also why I will be investigating the stall
characteristics of N914XL in straight and level, coordinated and uncoordinated
turns, clean and dirty, various weights and CGs, etc. with plenty of altitude
and in tiny increments to look for behavior defining the edges of the flight
envelope.
I too am baffled as to why a pilot with that level of experience would try to
turn
back when suitable areas to put it down are available within 30 degrees of
the departure heading. All I can think of is that he had practiced the 180 turn
to see how much altitude would be lost and had established such a turn-capable
altitude. (That attitude seems too be all too prevalent in some comments)
Then when the engine quit, he was above that altitude so he turned.
Unfortunately,
he did not account for the extra weight of the passenger or he did not
account for the fact that the turn is in actuality much greater than 180 or
different density altitude or some other factor we don't know.
I try to learn from every accident. Learning from Europa accidents has been too
frequent recently. My heart goes out to all those who have been affected by
the latest accidents.
Good building and great, SAFE, flying,
Bob Borger
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