What happened
On August 27, 2016, a Dornier Do 27 A-4 departed from Speyer Airport (EDRY) for a scheduled aerial photography mission. The flight was intended to capture "air-to-air" footage of another historical aircraft with the Hambach Castle as a backdrop. On board the aircraft were the pilot and four passengers.
Approximately 12 minutes into the flight, while cruising at roughly 1,600 ft AMSL, the engine began to sputter and eventually failed. The pilot attempted to restart the engine using the throttle, mixture, and fuel injection controls, but these efforts were unsuccessful. Due to the low altitude, the pilot focused on an immediate forced landing rather than further restart attempts.
Seeking a suitable landing site, the pilot evaluated nearby options but determined that the L 516 road was too heavily trafficked with vehicles to use safely. Instead, the pilot targeted a narrow asphalt farm track. During the descent, the pilot intentionally steered the aircraft into a grassy verge to avoid drifting onto the adjacent public road. The aircraft subsequently struck several trees, resulting in the destruction of the airframe. The four occupants sustained four minor injuries and were able to exit the aircraft.
The investigation
The BFU investigation examined the aircraft's fuel system, the pilot's pre-flight actions, and the environmental conditions. Investigators found that the fuel selector switch had been set to the right tank prior to the engine failure. A photograph taken by a passenger shortly before the failure revealed that while the left tank contained approximately 70 liters, the right tank gauge indicated "empty."
The investigation also noted that the aircraft's fuel system, a Lycoming-GO-480-B1-A6 engine, required constant fuel pressure. The investigation found that the pilot had been managing "increased activity" during pre-flight preparations, which were delayed because the second aircraft was not yet ready for departure. This delay left the crew waiting in an extremely hot cockpit.
Findings
- The primary cause of the engine failure was fuel exhaustion in the right tank.
- The pilot had selected the right tank for fuel supply, which was nearly empty, likely due to an oversight during the pre-flight checklist.
- The extreme heat in the cockpit and the high level of activity during preparations contributed to errors in the checklist execution.
- The lack of altitude reserve at the time of the engine failure left very little time for emergency procedures.
- The terrain, characterized by dense vineyards, significantly limited the available options for a safe emergency landing.