First I would like to extend my sincere condolences to the family of the Legacy pilot.  I was at Sun-N-Fun Friday and Saturday and saw the airplane.  I was a beautifully built aircraft and I was hoping to meet the owner but never got the opportunity.

I don’t know how old the airplane was or how long the engine had been hanging on the mount, but it usually happens that the engine will sag in the mount over time.  This is a normal thing and causes only cosmetic problems.  Sometimes in sever cases in a tightly cowled engine the exhaust pipes or some of the baffling will begin to rub.  Lycoming engines with the alternator mounted on the front will sometimes wear a hole in the lower cowling from the pulley rubbing.  This doe’s not cause loss of control nor doe’s a broken engine mount unless the engine comes off.  I have seen quite a few ag aircraft land with broken engine mounts from hours of high stress turns and countless landings on rough runways.  You usually experience a new vibration.

What can cause loss control is a canopy that is hinged at the front and comes open in flight.  About 10 years ago my son and I were test flying a Lancair 320 with a forward hinged canopy.  The latch looked overbuilt consisting of a ½” threaded bolt with a knob on it.  You closed the canopy and screwed the bolt that was mounted to the canopy bulkhead into a receptacle in the rear of the canopy.  The tighter you turned it the tighter the canopy pulled down onto the canopy seal.  Crude but effective.  We went out for about a half hour flight to get familiar with the airplane.  As we were descending to pattern altitude, the receptacle in the canopy frame that the bolt screwed into, pulled out of the frame and the canopy came open.  It popped up about 4 to 6 inches at the rear.  When it popped up, the nose pitched up sharply.  I countered by pushing forward on the stick.  The canopy dropped down in the rear and the nose now pitched down sharply.  I now had the power to idle trying to slow down.  As the nose pitched down, I countered by pulling back, the nose suddenly pitched up again.  This was not a pilot induced movement, it seemed that the canopy was flying straight and level and the airplane was pitching up and down around the hinge point.  My son was finally able to get his hands on the rear of the frame and pull it down and the pitching stopped.  While flying the pattern to land, we tried moving the canopy up and down and found that it controlled the pitch.  Push the canopy up and the nose pitched up, pull it down and the nose pitched down.  If you did not hold it stable in one position, it was almost impossible to control the pitch of the airplane.  Also, the higher the speed the worse the condition became.  If my son had not been with me and had the presence of mind to get hold of the canopy, I am not sure I could have gotten it under control by myself. 

Always make sure the canopy is locked before takeoff.  While the forward hinged canopy seems like the safest way to go, it may not be.  Some aircraft have forward hinged canopies and seem like the least desirable, but these are usually designed to rip off in the event it comes open.  The Glasair uses a Gull wing that is designed to rip off if it comes open.

The forward hinged canopy is not a bad design.  I just has to be locked in flight.  I worry that some people don’t worry about it coming open because they figure it will just ride stable until you can close it.  This can be a very dangerous attitude.

Happy Landings.