What happened
On January 14, 2004, an Aerostar Yak 52 departed from Koblenz-Winningen Aerodrome for a local flight. After approximately one hour of flight, the airfield control tower was unable to establish radio contact with the aircraft. A missing aircraft report was filed later that afternoon.
Following an extensive search by police, rescue services, and private volunteers, the wreckage was located on January 21, 2004, in a forested area near Stephanshausen, approximately 7 km northeast of Rüdesheim. The aircraft had struck the terrain in mountainous, wooded terrain with a 20-degree longitudinal pitch at high energy, resulting in the destruction of the aircraft and two fatalities. Witnesses reported seeing the aircraft performing aerobatic maneuvers prior to the crash.
The investigation
The investigation examined the wreckage, radar records, and witness statements. Investigators found that the aircraft was operating under Lithuanian registration and had undergone a major overhaul by a Lithuanian company in late 2003. While the pilot was undergoing training for aerobatic authorization, his specific authorization to fly Lithuanian-registered aircraft had expired in October 2003.
Technical analysis of the wreckage revealed that a small metal ball, identified as a fastener knob from the rear canopy, was located within the rear fuselage. Forensic examination of the elevator control mechanism and the fuselage opening showed clear evidence of physical contact between this loose knob and the elevator control rod. The investigation also noted that the aircraft's transponder was found switched off, and it was not equipped with an Emergency Locator Transmitter (ELT).
Findings
- The primary cause of the accident was a foreign object in the fuselage that moved during flight, significantly restricting the movement of the elevator control mechanism.
- The loss of control authority prevented the pilot from maintaining level flight and avoiding obstacles.
- The loose metal knob had detached from the canopy and migrated into the rear fuselage area where it became lodged against the elevator drive segment.
- The pilot was performing aerobatic maneuvers without the necessary authorization at the time of the accident.