What happened
On July 13, 2013, a pilot departed from Nordhorn-Lingen airfield (EDWN) for a flight to Münster/Osnabrück (EDDG) in a Xenon II gyrocopter. Approximately 12 minutes into the flight, while cruising at roughly 2,400 ft AMSL near the Emsland Nuclear Power Plant, the pilot experienced a sudden, loud bang. This was immediately followed by a perceived drop in altitude and a significant change in the aircraft' and horizon's orientation, initiating a left-hand turn and a rapid descent.
The pilot reported that the aircraft entered an unexpected inverted position with negative G-forces. In an attempt to stabilize the flight, the pilot moved the throttle to idle and held the control stick in a neutral position. The aircraft eventually leveled out in a nose-low, slipping attitude, leading to a steep descent toward a cornfield. During this phase, the pilot noted that the aircraft became largely unresponsive to control inputs and throttle applications, and the engine noise was notably absent despite the ignition being on and the charging light being illuminated.
In the final moments of the descent, the pilot managed to steer the aircraft toward a farm track bordering a wooded area. The Xenon II landed heavily on the track, positioned between the road and the edge of the field. The pilot sustained minor injuries to his leg, while the aircraft suffered heavy damage.
The investigation
The BFU examined the aircraft and the site of the accident. Physical inspection of the Xenolog II revealed damage to the rotor blades, landing gear, propeller blade tips, tail boom, and rotor head. Investigators found no evidence of mechanical failure in the control linkages or the rotor head bearings, which rotated freely without signs of overheating. The fuel tank contained approximately 43 liters of fuel at the time of the incident. A witness observed that the engine sound was irregular and stuttering prior to the emergency landing, though engine noise was not noted during the final descent.
Findings
- The aircraft experienced a sudden disturbance characterized by an audible bang and a subsequent loss of flight stability.
- The pilot encountered a period of unresponsive flight controls and a lack of engine power/noise during the steep descent.
- The aircraft was operating at a total weight of approximately 400 kg, well within its maximum takeoff mass of 450 kg.
- Meteorological conditions were favorable, with clear visibility and stable air.