What happened
On August 24, 2008, a Diamond Aircraft Industries, Katana DA 20-A1, registered OE-AKG, was performing a private VFR flight from Hohenems-Dornbirn to Lausanne-La Blécherette. The flight, carrying a pilot and one passenger, proceeded normally until the final approach phase for runway 18. During the last turn before the final approach, the cockpit canopy began to open on the right side, allowing air to rush into the cabin. The passenger attempted to hold the canopy closed, but eventually had to let go.
Witnesses on the ground observed the canopy in an open position and noted the aircraft oscillating heavily before it pitched down sharply. The aircraft struck a plowed field approximately 500 meters from the runway threshold, resulting in two serious injuries. The impact destroyed the aircraft and caused a small engine fire, which was extinguished by a bystander.
The investigation
Investigators examined the wreckage and interviewed witnesses, including the passenger and an airfield official. The investigation focused on the mechanical state of the canopy locking mechanism and the aircraft's maintenance history. While the locking hardware was found to be functioning normally, the right-side lever was found in the open position while the left was closed.
Technical analysis revealed that the aircraft had been flying for 147 hours since its last 100-hour inspection, with no documentation provided to verify the completion of that check. Additionally, while the aircraft was equipped with a 'Canopy/ECL' warning light, the flight manual lacked any emergency procedures for when this light illuminated during flight. The investigation also noted that the pilot's class rating extension had not been officially ratified by the relevant authority.
Findings
- The primary cause of the accident was a loss of control following the mid-flight opening of the cockpit canopy.
- The exact reason why the canopy unlatched could not be determined.
- The aircraft's weight and center of gravity were within limits, and sufficient fuel was on board.
- The engine and propeller showed no signs of mechanical failure prior to the impact.
- There was a lack of documented maintenance for the airframe and engine following recent intervals.
- The flight manual did not provide instructions for handling a canopy warning light during flight.