What happened
On the morning of May 7, 2011, a pilot operating an Evektor Eurostar EV97 ultralight aircraft departed from Nördlingen airfield for a series of local circuits, with plans to fly to Donaueschingen to pick up a passenger. The flight proceeded normally through the initial climb and the pattern until the downwind leg of the approach.
During the downwind leg, a loud bang occurred, and the cockpit canopy suddenly popped open to an angle of approximately 30 to 45 degrees. The pilot reported that this opening disrupted the airflow over the tail unit, significantly affecting flight controls. While the pilot attempted to close the canopy with his left hand and shorten the approach to land, he was unable to increase engine power sufficiently to compensate for the aerodynamic drag caused by the open canopy.
The airfield controller observed the aircraft flying unusually low and unstable near the runway. Despite attempts to contact the pilot via radio, there was no response. During the final part of the approach, the aircraft suddenly veered to the left and collided with a row of trees. The impact left the pilot seriously injured and caused heavy damage to the aircraft.
The investigation
The BFU examined the wreckage and the flight sequence. The investigation focused on the cause of the canopy failure and the subsequent loss of control. Investigators inspected the Evektor Eurostar EV97 and found no mechanical defects or restrictions in the flight controls. The aircraft's maintenance history showed a recent annual inspection in August 2010, and a previous manufacturer's airworthiness directive regarding material quality had been addressed in March 2010.
Findings
- The sudden opening of the cockpit canopy caused aerodynamic disturbance over the tail unit, leading to impaired control.
- The pilot was unable to maintain sufficient airspeed to counteract the increased drag from the open canopy.
- The aircraft's flight path became unstable and low during the final approach, resulting in the collision with trees.