Tuesday, September 4, 2012

Canopy Latch Handle

About a year ago I was practicing landings over at Quakertown. Satisfied with the progress I had made that day it was time to depart. Shortly after take off the canopy began to rise a little bit. I considered a landing attempt but it was already too late for that so instead I was forced to go around. Fly the airplane, Fly the airplane, Fly the airplane.

Climb to the downwind was normal. Level off was fine, although I did notice the wind noise. I stayed below 75 knots the whole time and was beginning to think it was a 'non-event' until I turned on base. As the nose pitched down, the canopy went up. More wind noise and something behind my seat was trying to escape. It turned out to be my sun cover and a chart or two. 

I had no controlability issues. I was distracted and really had to concentrate on the basics. I made a normal, full flap landing and safely taxied off the active runway. I diligently went through the take off check list again, triple checked that the canopy was down and latched and flew home. Now I always check the handle position, push up on the center of the canopy and visually check both sides to insure each latch is engaged.

This is a good description and video of a canopy open in flight.

I figured that was all there was to it until I started reading some posts on the yahoo group board. We had all been waiting for the reults from an investigation on a PiperSport that had crashed in Florida last year.

Looking aft
The NTSB has just posted the Factual Report on the May 6, 2011 fatal accident of a Piper Sport in Florida. The unusual aspect of the accident is that the pilot's body was found 1800 feet from the aircraft wreckage. Based mostly on the location of abrasion marks on the pilot and the location of baggage items extending from the flight track to the crash site, the report suggests that the pilot's seat belt was unbuckled, maybe while reaching for something in the back, and the canopy opened in flight with a suggestion that either a loose shoulder harness or a headset cord wrapped around the canopy release and opened it. (Full report)
..and there was this from a friend flying in Hawaii, who bought his plane the same week I bought Sally.

To add a little to the discussion on this topic: A fellow pilot flying my Piper Sport did experiance the canopy opening at about 100 knots. The result was a violent pitch down, the canopy going almost vertical and the negative G ejection of everything lose in the baggage compartment (manuals, camera, sun cover, chocks, etc.) He got pitch under control, slowed to 65 kts and landed with no damage. Lessons: (1)NEVER unbuckle the seat belts in the air. (2) The canopy opened because only one of the catchs engaged and the "push up on the canopy" preflight check will not catch this condition. Best to do a visual; check of both sides also.
Looking down

Joe Kiefer
As a group the PiperSport/Sport Cruiser owners started thinking of additional safeguards.  Today I experimented with a bungee approach. I don't particularly like purple, but this might be effective. I like it because it is simple, it keeps the belts and cords from getting underneath the handle and its easy to install. We're still looking for good ideas, please don't hesitate to offer them.








2 comments:

  1. In adding an internal lock or bungee mechanism you are balancing the risk of the pilot accidentally opening the canopy inadvertently against the inability of external assistance to access the cockpit quickly in the event of a crash landing and pilot incapacitation.

    Hopefully both scenarios are very remote possibilities, but for me the unstrapped inadvertent cockpit opening seems more unlikely than the need for external assistance, so I would rather not fit any internal lock or restraint beyond the force already required. Anyone really concerned about the inadvertent opening risk would be better of fitting either a 'lift to access cover' on the internal handle (perhaps not great if you need to exit the cockpit quickly) or a couple of metal guard rails alongside the canopy latch (similar to those often placed alongside the ignition switch) to prevent any cables inadvertently tangling around the latch.

    Piers

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  2. Good job on flying the plane!!

    I have had my share of open doors so I understand the "fly the plane"! I added to the visual check with a push of my shoulder on the door and running my hand along the bottom of the door to make sure there is no "air" gap.

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