What happened
On 22 December 1999, a Robinson R22 Beta, registration G-EPAR, was involved in an accident at Blackpool Airport, Lancashire, during an aerial training flight. The flight was being conducted as part of an instructional session for a new student.
As the flight concluded, the instructor attempted to demonstrate the procedure for recovering from an engine failure while performing a hover taxi. From an altitude of approximately four feet, the instructor simulated an engine failure. At the time, the aircraft was experiencing a 15-knot wind from its 5 o'clock position. Upon closing the throttle, the pilot found that the aircraft began to yaw to the left. Despite the application of full right pedal, the yaw could not be corrected. The helicopter descended into the grass with forward motion and a right sideslip. As the right landing skid dug into the soft ground, the aircraft rolled onto its right side.
There were no injuries to the two occupants, though the aircraft sustained substantial damage to the cockpit structure, tailboom, and main rotor blades, resulting in it being declared an insurance write-off.
The investigation
Investigators reviewed the accident report submitted by the pilot and conducted telephone inquiries. The investigation focused on the mechanics of the maneuver and the environmental conditions at the time of the incident. The inquiry examined the interaction between the aircraft's flight characteristics, the wind conditions, and the ground surface during the simulated failure.
Findings
- The aircraft's narrow landing gear track and the unusually high position of the main rotor system make the R22 susceptible to dynamic rollover.
- The low inertia of the rotor blades makes attempting an engine-off landing during a hover taxi a high-risk maneuver.
- The presence of a tailwind component increased the risk of the maneuver by reducing the pilot's ability to maintain yaw pedal authority.