What happened
On July 6, 2014, an Alpi Aviation Pioneer 400 departed St. Johann (LOIJ) in Austria, bound for Bad Endorf (EDPC), carrying three occupants: the pilot and two passengers.
During the approach to the grass runway at Bad Endorf, the aircraft experienced a hard impact with the ground. Following this initial contact, the pilot attempted to continue the flight, performing two low passes. During these passes, the air traffic controller at Bad Endorf observed that the left main landing gear was not properly extended. After the second pass, the aircraft was observed performing steep turns near the village of Halfling. As the aircraft lost altitude, the pilot was unable to return to the airfield, and the aircraft subsequently landed in a wooded, marshy area near Rundorf, approximately 2,000 meters west of the Bad Endorf aerodrome.
The impact resulted in one serious injury to the pilot, while the two passengers remained unharmed. The aircraft sustained heavy damage.
The investigation
Investigators examined the wreckage and the aircraft's mechanical systems. The investigation focused on the state of the retractable landing gear and the cause of the initial hard landing. The BFU also reviewed the pilot's credentials, noting his 237 hours of total flight experience and limited experience specifically with the Pioneer 400 model. Meteorological data indicated clear visibility and light winds at the time of the accident.
Findings
Technical examination of the Alpi Aviation Pioneer 400 revealed that the left main landing gear was stuck in the gear well, with only one-third of the strut extended. The investigation identified a broken ball joint at the wing attachment point. Furthermore, while the landing gear lever was in the 'DOWN' position, the 'GEAR' fuse was found to be blown. An inspection of the electric retraction motor revealed that a deformed spindle shaft prevented the motor from rotating, which had triggered the circuit breaker.
Additionally, the nose gear had collapsed due to a broken ball joint, and the propeller sustained damage, including a broken blade tip.