What happened
On May 18, 2015, at approximately 07:33 UTC, a Piper PA 23-250 was preparing for a planned aerial photography flight near Bad Vöslau, Austria. After refueling with 128 liters of AVGAS and completing engine magnet checks, the pilot aligned the aircraft with runway 13.
As the pilot applied full power and attempted to release the main brakes, the left main landing gear collapsed. This caused the left propeller to strike the asphalt runway surface. The pilot immediately shut down both engines and notified the airport manager of the loss of control. The pilot, a passenger, and a camera operator were able to exit the aircraft without injury, though the aircraft sustained significant damage.
The investigation
The SUB examined the wreckage and the aircraft's technical components. Investigators found that the left main gear strut had lost its connection to the overcentering strut. Specifically, the bolt connecting the front and rear struts was found broken into two pieces.
Additionally, the investigation reviewed the aircraft's weight and balance. The SUB determined that the aircraft's takeoff mass exceeded the manufacturer's maximum takeoff weight (MTOW) by approximately 30.4 kg. The calculated weight at the time of the accident was 2389.08 kg, while the MTOW was limited to 2358.6 kg.
Findings
- The primary cause of the accident was a combination failure of the connecting bolt between the overcentering strut and the left main landing gear shock absorber.
- Technical analysis of the bolt revealed a notch on the outer diameter, which likely served as the origin of a fatigue crack, followed by a secondary brittle fracture.
- The aircraft was operating in an overweight condition, exceeding the maximum takeoff weight by 30.4 kg.
- The pilot was properly licensed and in good health at the time of the occurrence.