What happened
On 4 August 2009, a Westland Bell 47G-3B-1, registration G-BFYI, was involved in an accident at Bagby Airfield in North Yorkshire during a private flight. After arriving from Windermere, the pilot performed a hover-taxi to a fuel pump located near the airfield clubhouse. The weather conditions at the time featured a strong surface wind from 100° at 20 knots, with gusts reaching 30 knots.
While the pilot was executing a sideways hover-taxi to the right, a sudden gust of wind caught the vertical tail surface of the aircraft. This caused the helicopter to yaw rapidly to the right. In an attempt to regain control, the pilot applied full left pedal and increased collective pitch to raise the aircraft's height while attempting to maintain a level pitch. Despite these efforts, the tips of the tail rotor blades struck the concrete surface of the parking area. The resulting vibration was severe enough that the pilot performed a running landing on a nearby grass area and shut down the engine.
The investigation
The investigation was based on the aircraft accident report submitted by the pilot. The inquiry examined the flight sequence, the environmental conditions, and the pilot's control inputs. The investigation established that the aircraft sustained damage to the tips of both tail rotor blades. The pilot's assessment indicated that the suddenness of the wind's impact on the vertical stabilizer prevented effective recovery of the aircraft's heading.
Findings
- The primary cause of the accident was the strong and gusting wind acting on the vertical tail surface, which induced a rapid rightward yaw.
- The pilot was unable to maintain sufficient clearance for the tail rotor due to the speed of the event and the magnitude of the control inputs required.
- The aircraft was operating in wind conditions that, while within the pilot's perceived limits, proved critical due to the gusting nature of the wind.