History of the Flight
The pilot, accompanied by five passengers, took off from Aix-Les-Milles aerodrome bound for Toussus-le-Noble aerodrome with a stop at Clermont-Ferrand airport. After refuelling and re-embarking passengers, the pilot started the engine. On entering hover, the helicopter turned rapidly around its yaw axis several metres from the ground. After approximately two turns, the pilot, unable to stop the rotation, lowered the collective pitch control to bring the helicopter to the ground. The helicopter landed hard and bounced before coming to a stop. After engine shutdown, all occupants evacuated.
Examination of the Helicopter
Several examinations were performed on site and in the workshop. Continuity of flight control linkages and operation of servocontrols and yaw trim were checked. The mechanical connection between engine and tail rotor was verified; the engine was supplying power to the tail rotor at the time of the accident. No anomaly likely to explain the loss of yaw control was detected. The helicopter was equipped with dual controls (cyclic pitch, collective pitch and pedals). Weight and balance showed the helicopter was near the maximum permissible take-off weight (2,200 kg) and within the permissible balance envelope.
Pilot Information
The pilot held a Private Pilot Licence - Helicopters (PPL(H)) issued in 2013 with approximately 470 flight hours, 200 in the R44 and 270 in the AS350. The AS350 type rating was obtained in 2017. In 2020, the pilot logged 52 flight hours in the AS350, two-and-a-half hours in the 24 hours preceding the accident.
Meteorological Information
Meteorological conditions observed from aerodrome surveillance camera footage at the time of the accident included a westerly wind of approximately 5 kt with gusts, broken clouds (altocumulus), and visibility greater than 10 km. The anemometer at the aerodrome was unavailable, as signalled by NOTAM.
Conclusions
On entering hover, it is likely that the pilot’s insufficient action on the right pedal caused the helicopter to rotate left around the yaw axis. Taking into account the proximity to the ground and the rapid rotation, the pilot wanted to gain height by increasing power required for the main rotor. This action increased torque to be countered by the tail rotor whilst reducing its available power and effectiveness. The yawing movement increased. Unable to regain yaw control, the pilot decided to bring the helicopter to the ground by lowering the collective pitch control.
Contributing factors may have included the pilot not controlling the position of the feet of the passenger sat in the front, given the presence of dual controls, which may have hampered pedal movement; and insufficient input of the pilot on the right pedal during hover, probably with a turbulent tailwind.