What happened
On 20 May 2014, an Aero L-29 Delfin, registration G-BYCT, was performing a private flight near Cranfield Airfield in Bedfordshire. Following a standard takeoff, the aircraft was climbing through an altitude of approximately 500 feet when the front right section of the canopy lifted by about one inch. In an attempt to pull the canopy back down into position, the component became completely detached from the airframe. The pilot managed to land the aircraft safely and without damage, and there were no injuries to the two crew members on board.
The investigation
The investigation focused on the mechanical state of the canopy and its securing mechanisms. The canopy is held to the airframe via two hinges located on the right side and is held closed by four latches, distributed as two on each side. The pilot noted that verifying the engagement of the hooks within the latches is a difficult task. To ensure security, the pilot typically performs a manual check by pushing upward on the left side of the canopy after locking it.
Investigators examined the possibility that the hinges on the right side were binding. It is suspected that this binding resistance prevented the hooks on the right side from fully seating into their respective latches.