Aircraft and Flight Information
The accident aircraft was a Diamond DA42-P7, registration OE-FCD, owned by Diamond Aircraft Industries GmbH and operated by SC AERO GETIC SRL. On 25 September 2007, the aircraft was conducting ground laser scanning flights over the Oltețului Valley area. The second flight of the day departed from Craiova International Airport at 14:21 local time after a refueling delay. On board were the pilot and an operator of the scanning system.
Accident Sequence
During the flight, after scanning a segment of the planned route, the pilot experienced a sudden pitch change of the right-hand propeller blades into the feather position, resulting in an immediate engine stoppage. The pilot did not secure the propeller of the stopped engine in the feather position by moving the power lever to zero/feather and turning the Engine Master Switch off. Consequently, the propeller pitch changed from feather to the start-lock position, increasing aerodynamic drag.
The pilot was unable to maintain a climb rate. The aircraft's weight exceeded the maximum permitted limit, and its center of gravity was outside the manufacturer's recommended range. The aircraft began to descend. The pilot deployed flaps at an inappropriate speed and altitude, leading to a loss of control. The aircraft stalled on the right wing, entered an uncontrolled dive, and struck the ground at an estimated speed of 85 knots in an almost vertical trajectory.
Investigation Findings
The investigation determined that the engine failure resulted from a malfunction of the propeller pitch regulating valve (PPRV). The pilot's failure to secure the feathered propeller contributed to increased drag. The aircraft was operated with a belly pod scanning system configuration, and the pilot was unable to maintain control with one engine inoperative under those conditions. Additional factors included the aircraft being overweight, an out-of-limits center of gravity, and the working altitude below the surrounding mountain peaks.
Probable Cause
The probable cause of the accident was the inability to control the aircraft attitude with the belly pod scanning system configuration during single-engine flight. The engine stoppage was due to a malfunction of the propeller pitch regulating valve. Favoring causes included the stopped engine propeller pitch moving from the feather position, aircraft weight exceeding the maximum limit, center of gravity outside limits, and working height below surrounding mountain quotas.