Accident Overview
On 10 May 1999, a Piper PA-44-180 aircraft operated by an unknown entity was conducting a training flight from Hamburg Airport to Rendsburg-Schachtholm. The flight was part of a commercial pilot license program, with dual controls. After several touch-and-go landings at the destination, the flight instructor announced the intention to land. The approach was abandoned during the short final phase. During the go-around, the aircraft struck a group of trees with its underside, located approximately 150 meters left of the runway within the airfield boundary. It then struck the roof of a hangar situated immediately beyond the trees and impacted nearly vertically on the hangar apron. Both occupants were killed, the aircraft was destroyed, and the hangar sustained damage.
Investigation
The German Federal Bureau of Aircraft Accident Investigation (BFU) assigned two investigators to examine the accident. No witnesses observed the entire sequence; only the final moments were witnessed by some individuals. Radar data was unavailable because the aircraft remained below radar coverage during the approach. The absence of witnesses and definitive technical evidence precluded a complete reconstruction of the accident sequence.
Wreckage Examination
Examination of the wreckage revealed the following:
- The landing gear was extended and locked; the selector lever was in the extended position.
- Both engines' carburetor heat controls were in the warm position.
- The flaps were found in the retracted position, but the flap handle was deformed in an intermediate position due to impact, making the actual flap setting uncertain.
- Both propellers showed evidence of rotation at ground impact, but no definitive determination of engine power output was possible.
- The right engine spark plugs indicated normal combustion, while the left engine spark plugs were slightly sooty, suggesting a rich mixture.
- No mechanical damage was found on either engine.
- The throttle, propeller pitch, and mixture controls were set to full power, high RPM, and rich mixture, respectively.
The fact that carburetor heat was applied reduces engine power. Combined with the extended landing gear, this would result in relatively poor climb performance, but does not explain why the aircraft deviated 150 meters to the left of the runway. A partial or complete power loss of the left engine was considered a possible explanation, but apart from the rich mixture indication, no supporting evidence was found.
Conclusion
Despite the investigation, the cause of the accident could not be determined.