NTSB Report on Bill Phillips' Accident

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