What happened
On July 19, 2022, a pilot was performing the final leg of a delivery flight in a newly purchased AutoGyro MTOsport 2017. After picking up the aircraft in Hildesheim and making a scheduled stop in Giebelstadt for refueling, the pilot contacted the Mengen-Hohentengen airfield at approximately 19:09 to announce his arrival.
While executing the landing pattern for runway 07, the aircraft suddenly lost altitude and rolled sharply to the right. Witnesses observed the aircraft descending at a steep angle, noting that the engine noise increased significantly while the main rotor blades appeared to be rotating very slowly. The gyroplane struck a cornfield approximately 230 meters before the threshold of runway 07. The impact was followed by an immediate and intense fire that destroyed the aircraft and resulted in one fatality.
The investigation
The BFU examined the wreckage, engine parameters, and flight data recovered from the engine's electronic control unit. The investigation included an analysis of the pilot's flight history, which showed approximately 168 hours of experience, primarily in previous models of the same aircraft type. Medical examinations of the pilot ruled out sudden medical emergencies, such as a heart attack or stroke, as a cause for incapacitation.
Investigators also reviewed the aircraft's mechanical integrity. There was no evidence of mechanical failure in the flight controls, the engine, or the rotor head. The investigation focused on the aerodynamic conditions during the final approach, specifically looking at the vertical acceleration (G-load) recorded by the engine's data logger.
Findings
Data from the engine control unit revealed that the pilot had reduced engine power during the approach. Following this power reduction, the vertical acceleration decreased, indicating a period of low G-loading. The investigation concluded that the pilot likely pushed the control stick forward to initiate a descent, a maneuver known as a "push-over."
This maneuver caused a massive loss of rotor RPM and a subsequent loss of control over the roll axis. The sudden reduction in G-load, combined with the pilot's attempt to descend, led to the aerodynamic instability that caused the aircraft to roll and plummet into the field.