What happened
On September 25, 2021, a Magni Gyro M 24 Orion gyrocopter departed from the "Pfingstweide" glider airfield in Butzbach, Germany, for a planned return flight to Worms. The aircraft was carrying a pilot and one passenger. Witnesses recorded the takeoff from the asphalt strip of runway 10, noting a steady and rapid acceleration. The aircraft lifted off after approximately 150 meters, initially climbing to a height of about 3 meters before the rate of climb increased, bringing the aircraft to the height of the treeline.
Shortly after passing the treeline, the aircraft continued its flight path toward rising terrain. The flight was not observed by witnesses beyond this point. The sound of the rotor striking trees alerted onlookers, who then observed smoke rising from the forest. The gyrocopter had collided with trees approximately 235 meters beyond the forest edge and crashed onto a forest path, where it immediately caught fire. Both the pilot and the passenger sustained two fatalities due to smoke inhalation following the impact.
The investigation
The BFU examined video footage of the takeoff and initial climb, as well as the wreckage and medical findings. The investigation confirmed that the aircraft was in a controlled flight state at the time of the collision, evidenced by the vertical descent through the trees. The autopsy revealed that while the impact itself did not cause fatal injuries, the occupants died from smoke inhalation.
The investigation also reviewed the aircraft's technical specifications, noting that the seat and backrest structures also functioned as part of the 82-liter fuel tank. The BFU also examined the environmental conditions, including the high density altitude caused by warm temperatures, and the presence of stainless steel erosion protection strips on the rotor blades.
Findings
- The primary cause of the accident was insufficient airspeed, which led to a significantly reduced rate of climb while flying over rising terrain.
- The aircraft was flying at a speed that likely placed it behind the power curve, where maintaining altitude becomes impossible.
- Contributing factors included an increased density altitude due to high ambient temperatures, which likely reduced engine performance.
- The lack of a headwind component meant the aircraft could not utilize additional airspeed to clear the obstacles.
- The presence of stainless steel erosion protection strips on the rotor blades may have further degraded aerodynamic efficiency and lift.
- The immediate fire following the impact was exacerbated by the fact that the fuel tank was integrated into the seat structure, making the occupants vulnerable to fuel ignition upon impact.