Accident Overview
On 9 April 2000 at 1649 UTC, a Hughes 369HS helicopter (registration G-BPLZ) was conducting a hover taxi toward the fuel facility at Wolverhampton Business Airport. As the helicopter touched down on a heading of approximately 170°, it began an uncontrolled left rotation. After one complete revolution, the helicopter briefly became airborne and the rate of turn increased, spinning rapidly through another half turn before coming to rest upright adjacent to the fuel bowser. The pilot shut down the engine and discovered that the tail boom had been severed. The helicopter sustained damage to the tail rotor blades and tail boom. The occupants, one pilot and one passenger, reported no injuries.
Operational Details
The flight was conducted under a Private Pilot's Licence. The pilot, aged 50, had accumulated 71 total flying hours, of which 29 were on the Hughes 369HS type. In the previous 90 days, he had flown 4 hours, including 2 hours in the last 28 days.
Meteorological Conditions
An aftercast from the Meteorological Office indicated that at the time of the accident, the surface wind was from 060° at 16 kt, with gusts likely reaching 25 kt. The landing attempt was made with a crosswind from the left side.
Engineering Findings
An engineering inspection found no damage to the main rotor blades. There was no evidence of any mechanical failure in the tail rotor drive system or the tail rotor gearbox mounting. However, the tail rotor flapping stops were destroyed. The normal clearance between the tail rotor blade tips and the tail boom is approximately 3 inches. The combination of low rotor RPM and high yaw pedal demand could have allowed the tail rotor to flap excessively during the gyration, causing pounding damage to the flapping stops, followed by the blades contacting the tail boom.
Pilot Actions and Observations
The pilot initially assessed that the helicopter began to rotate to the right and applied left pedal to counter it. A video recording of the event showed that the helicopter actually rotated to the left. The tendency to rotate left was exacerbated by the crosswind from the left side.