What happened
On February 18, 2016, a privately operated DG Flugzeugbau Extra 300, registration D-EFBY, was performing a takeoff from runway 19 at the Valence Chabeuil aerodrome. Shortly after the aircraft reached rotation speed, the canopy opened unexpectedly and struck the upper surface of the right wing.
Fearing the canopy might detach completely and strike the tail section, the pilot elected to abort the takeoff. The pilot attempted to land at the threshold of runway 01; however, the remaining runway length was insufficient to stop the aircraft. The aircraft exited the runway longitudinally, crossed a road, and struck the aerodrome perimeter fence. The impact ruptured the right wing fuel tank, causing the aircraft to catch fire. The pilot sustained slight injuries and successfully evacuated the aircraft before firefighters arrived to extinguish the flames.
The investigation
The BEA examined the aircraft's canopy and locking mechanism, which utilizes two handles to engage pins into the fuselage structure. While the spring-loaded locking system was found to be functional, investigators discovered that the handles could remain in an intermediate position between the locked and unlocked states.
Testing revealed that a slight misalignment between the locking pins and the fuselage tenons could prevent a full lock. Because the chamfered ends of the pins and the spring tension were insufficient to correct this misalignment automatically, manual pressure on the handles is required to ensure a secure lock. The investigation also noted that the flexible nature of the single-piece canopy structure might contribute to such misalignments.
Findings
- The pilot did not detect that the canopy handles were incorrectly positioned.
- The canopy was not properly locked, causing it to open during rotation.
- The remaining runway distance during the aborted landing attempt was insufficient to prevent the longitudinal excursion and subsequent collision with the perimeter fence.