On Sep 26, 9:38*pm, brian whatcott wrote:
Peter Dohm wrote:

...

1) * *Was the canopy open/unlatched?
* * * * (It very probably was)
2) * *Could this happen to an unimpaired pilot?
* * * * (Obviously yes, since it has happened several times)
3) * *Could an open/unlatched canopy be prevented, or
* * * * could the results be mitigated in a cost effective way?
* * * * (I think so, and think it needs further discussion)

As Stealth has pointed out, those canopies appear not to be a fail safe
design. *One would initially presume that they would only open slightly and
maintain a slightly open position in trail, which was true in at lease one
instance and might presumably have been true of the test aircraft. *However,
at least one other example appears to have behaved quite differently and I
personally doubt that the difference in shape would need to be much greater
than the thickness of a coat of paint to cause a dramatic difference in
behavior.

I suspect that a safety catch of a type common on the engine hoods of
automobiles and placed close enough to the latched position to preclude
oscillation, accompanied by the installation of a warning lamp when the
canopy is not in its fully latched position, would both mitigate the result
of an unlatched canopy and make the occurence less likely.

I still would not personally choose a hinged canopy; but those improvements
should be sufficient to render my other criticisms nearly moot.

Peter

Side and forward hinged canopies can lift in the airstream. * *This
would not be a "gee-whiz how could that happen" type of problem.
I have reported my own stone-cold sober experience with a side hinge top
canopy unlatching at takeoff and I would be surprised to hear of side
and front hinged canopies that DON'T lift in the air stream.
Accordingly, I think a secondary catch sounds like a very, very sensible
idea. You can't imagine how distracting *it is 'til you experience it.
an inch or two of bobble would be a whole lot less threatening,
in my view.

Brian W

Sailplanes are adopting forward hinged canopies as a safety feature.
Any canopy opening system can open inadvertently if not properly
latched but the forward hinge system will open less violently than
other systems.

Regardless of the hinge system, an open canopy is not likely to render
an aircraft unflyable. The first priority is to FLY THE AIRCRAFT and
deal with the canopy on the ground after a safe landing.

Long experience has shown that the biggest hazard of an open canopy in
flight is the pilot trying to close the canopy and not flying the
aircraft while he's doing it. There's a history of glider accidents
with this scenario. Glider pilots are taught to assume an open canopy
is trashed, put it out of their mind and fly the glider as an open
cockpit aircraft.

As a standard part of training, I will have students open the canopy
in flight and enjoy a few minutes of open cockpit flying. The point
is for them to see that the glider flies just fine with the canopy
open so if it opens inadvertently, they aren't panicked.

Finally, one has to consider the effect of a large jolt of adrenalin
when added to Bill's drug cocktail. It's possible that he could have
dealt with flying the airplane under non-emergency conditions but not
with the stress and adrenalin of an open canopy.

Bill Daniels