What happened
On 2 February 2016, a student pilot was conducting a solo training flight in a Reims Cessna F152, registration G-BFEK, at Gloucestershire Airport. After completing several dual circuits, the pilot taxied to the A2 holding point for Runway 27 and waited for takeoff clearance. While stationary at the holding point, the aircraft suddenly pivoted on its nose and right main wheel.
The movement caused the propeller and the right wingtip to strike the ground. At the time of the incident, an EC145 helicopter was hover-taxiing behind the Cessna after completing a rotors-running refuel. The pilot of the G-BFEK observed a yellow helicopter in a low hover upwind of the aircraft just before the tip occurred. Following the impact, the pilot issued a PAN call, shut down the engine, and exited the aircraft via the passenger door to avoid the tilted cockpit.
The investigation
The investigation examined air traffic control recordings, airfield operator reports, and statements from the pilots involved. It was established that the EC1 and an R44 helicopter were both active in the area near the fuel pumps. The EC145 pilot had attempted to maintain maximum separation from both the Cessna and the R44 by taxiing close to the north side of the fuel pumps.
Analysis of the aircraft tracks indicated that the EC145 passed within approximately two to three rotor diameters of the G-BFEK. Meteorological data showed that while the pilot had reported a 13-knot wind, the METAR indicated stronger winds of 15 knots with gusts reaching 25 knots. The investigation also noted that the student pilot was holding well short of the actual stop line at the A2 holding point.
Findings
- The primary cause of the accident was the main rotor downwash generated by the EC145 helicopter as it hover-taxied near the stationary aircraft.
- The intensity of the downwash was likely increased by the prevailing wind speed and direction.
- The separation between the helicopter and the G-BFEK was within the range where downwash effects are most severe (two to three rotor diameters).
- The aircraft was positioned significantly short of the holding point line, which reduced the available buffer between the fixed-wing and rotary traffic.
Safety action
Following the incident, the airfield operator implemented several changes to manage the 'Hot Spot' area, including:
- Restricting or discontinuing rotors-running refuelling operations at the large 'H' sign.
- Implementing restrictions on the use of nearby landing spots (Spots 2 and 5) to prevent congestion near fixed-wing holding points.
- Encouraging fixed-wing operators to move closer to the holding stop lines to increase separation from rotary traffic.