What happened
On October 24, 2010, a Robinson R44 Raven II helicopter was conducting a flight from Oerlinghausen to a planned landing site near Altenbeken. The flight was intended to transport passengers to a local event at a discotheque. Upon approaching the target area, the pilot found the intended landing site—a parking lot—occupied by vehicles and pedestrians. Consequently, the pilot attempted to fly over the area to survey alternative landing options.
During the maneuvering, the helicopter flew at an altitude of approximately 200 to 300 feet above power lines. As the pilot executed a left turn to follow a field path, the aircraft began to lose altitude. Video footage and pilot testimony indicate that the aircraft experienced a significant loss of lift, accompanied by a low rotor RPM warning. The helicopter entered a descending state, struck trees, and became entangled in a telephone cable before impacting the ground with almost no forward airspeed. The aircraft landed on its left side, resulting in four serious injuries among the occupants.
The investigation
The BFU investigation examined the aircraft's maintenance records, the pilot's experience, and the environmental conditions. The aircraft was found to be in compliance with all maintenance and airworthiness requirements, and no mechanical failures were identified. The investigation also reviewed the pilot's credentials, noting he held a valid private pilot license with night flight qualifications and approximately 325 total flight hours.
The investigation focused on the aerodynamic state of the helicopter during the low-speed maneuvering. Investigators analyzed the flight path, the impact with obstacles, and the meteorological conditions, which included localized showers and gusty winds of up to 25 knots. The BFU also examined the regulatory context of the flight, noting that while an external landing had been authorized, the pilot was operating under a private license for a flight that had commercial characteristics.