Aircraft and Flight Details
The accident involved a Robinson R44 helicopter, registration G-POLT, manufactured in 1997. It was powered by a single Lycoming O-540-F1B5 piston engine. The flight was a private type conversion training session, returning to Cardiff Airport after approximately 30 minutes of training. On board were two crew and two passengers, all of whom were uninjured. The commander, aged 35, held a Private Pilot's Licence (Helicopters) with a Night Rating and Instructor Rating, and had accumulated 639 flying hours, including 38 hours on the R44 type.
Accident Narrative
The instructor, occupying the left front seat, was converting an R22-qualified pilot to the R44. The two rear-seat occupants were another R22-qualified pilot and a student helicopter pilot. The weather was fine with good visibility, few clouds at 3,500 feet, and a surface wind of 280°/12 kt. As the route passed near the instructor's home, he suggested demonstrating an approach and landing to a private site. He reduced forward speed and pointed out ground features and local dangers.
Descending through 50 feet with near zero airspeed, a sudden and very strong gust of wind yawed the helicopter to the right. Corrective left pedal input increased the rate of descent. Increased power failed to arrest the sink rate. The instructor then turned the helicopter to the left, attempting to gain translational lift by increasing airspeed. Close to the ground, he used the remaining power to cushion the landing onto sloping ground in an adjacent field. The helicopter rolled over and came to rest on its left side.
Pilot Information
The commander had 639 total flight hours, with 38 hours on the Robinson R44. In the previous 90 days he had flown 36 hours, and 10 hours in the last 28 days. He held an Instructor Rating and was conducting the conversion training.
Damage and Injuries
The helicopter sustained substantial damage to the left side of the fuselage and rotor assembly. All four occupants (two crew and two passengers) were uninjured and evacuated the helicopter via the right door.
Probable Cause
The instructor assessed the cause of the accident as an encounter with unexpected gusting wind conditions brought about by the mountainous nature of the local area.