What happened
On July 6, 1997, a Robinson R22 Beta II, registration I-RHII, was performing a flight from Grimaud to a private helisurface near the pilot's residence in Carros, France. As the pilot approached the landing area, the aircraft was positioned south for its final approach. At an altitude of approximately 15 meters, the pilot reduced airspeed and initiated a slight right turn to align with the landing pad.
During this maneuver, the aircraft began to yaw to the right. The pilot attempted to correct this movement using left pedal input, but the rotation intensified. At this point, the passenger, who possessed more experience on this specific aircraft type, took control of the flight instruments. In an attempt to avoid an obstacle—an anemometer located on a nearby garage—the passenger increased the collective pitch to gain altitude. This action further increased the reactive torque, exacerbating the rightward rotation. The helicopter subsequently lost control and crashed into a ravine among trees east of the helisurface. The crash resulted in two injuries and the destruction of the aircraft.
The investigation
The investigation focused on the mechanical condition of the aircraft and the aerodynamic factors during the landing phase. Investigators examined the wreckage and found no evidence of mechanical failure or prior impact. The tail rotor remained caught in a tree at approximately 12 meters, but examination showed no prior damage. The engine's power output was evaluated against the power required for the flight conditions. The investigation also ruled out a failure of the tail rotor drive shaft, noting that a sudden breakage would have caused an instantaneous, rather than progressive, loss of control.
Findings
- The aircraft was operating at a very low airspeed, near a hover, and was outside of ground effect due to the surrounding terrain and tree height.
- The pilot was operating the aircraft at the limit of available engine power.
- The requirement for additional power to counteract the increasing yaw and to maintain lift exceeded the maximum power available from the engine under the day's atmospheric conditions.
- The passenger's attempt to increase altitude via the collective pitch increased the reactive torque, which further accelerated the uncontrolled yaw.