What happened
On September 9, 2008, a Diamond DA 40 D departed from Egelsbach airfield, bound for Bonn-Hangelar. While flying northwest, approximately 14 nautical miles southeast of Koblenz, the pilot reported hearing a loud bang from the engine compartment. Immediately following this noise, the oil pressure dropped into the red zone and engine power decreased.
In response to the engine failure, the pilot prepared for an emergency landing in a harvested field near Kasdorf. During the final approach, the aircraft struck a cornfield before making a hard impact on the intended landing site. Despite the significant damage to the aircraft, the pilot and passenger were able to exit the wreckage without injuries.
The investigation
The BFU investigation focused on the mechanical failure of the engine and the circumstances of the landing. Examination of the engine revealed a significant opening in the area of cylinder number one. The connecting rod for this cylinder was missing, and the piston had been severely damaged, with the upper part of the piston found twisted within the cylinder bore. The investigation also found that the timing chain had broken following the initial failure.
While investigators identified that the installed turbocharger had been taken from a different, defective engine without proper documentation, they determined that this component did not contribute to the primary failure. The investigation also noted that the pilot's approach to the landing site left insufficient altitude reserves to compensate for unexpected wind conditions.
Findings
- The engine failure was caused by the failure of the connecting rod in cylinder number one.
- The pilot's assessment of wind effects during the emergency approach was inaccurate, leading to the aircraft striking an obstacle (the cornfield) before touchdown.
- The aircraft sustained heavy damage, including a destroyed landing gear, tailplane support, and wing-to-fuselage attachments.