Monday John Smith flew his superb Legacy down from Perth to my home drome to partake of some of our high energy 100 LL hangar coffee.  After solving problems of politics, world economics, and off-shore oil and gas technology (John is an oil and gas guy) we resumed our discussion about Legacy canopy safety latches. 

 

John brought a packet full of sketches and ideas, and in the last couple of days we have exchanged many more.  John is determined to find a solution despite the fact he has dual microswitches and a canopy warning that comes up on his EFIS.

 

Trained in HAZOPS (Hazardous Operations) and knowledgeable in evaluating failure modes and calculating disaster probabilities, he has concluded via some quick numbers that checklists, switches, indicators all combined do not provide the level of safety required to meet minimum error-proof safety levels for an incident that could yield a fatal outcome.

 

We were going to ground test the resonant oscillation of canopy theory I proposed here a few days ago, but concluded it was not worthwhile because you could never flight test a solution with oil/air damped gas springs to kill the resonance.  Moreover, recent reports that some Legacy aircraft have departed with canopy open and no incident occurring suggest that there are factors of speed, aircraft control, turbulence, power setting and such that must align (or not align) to cause or not cause the canopy problem.  No test program we could conduct could examine all the details.

 

So we return to the need for a simple, fail safe secondary latch that is easy to install and use, and easy for an external rescuer to find and release in the event of an accident that incapacitates the occupants.  Ideas and sketches are bouncing around, and it may soon be time for construction and evaluation of a prototype.

 

Stay tuned.  Volunteers may be needed to help. 

 

Fred Moreno