What happened
On 7 April 2006, a Robinson R22 Beta, registration G-OPAL, was conducting a basic helicopter training flight at Wycombe Air Park. The flight involved an instructor and a student performing various maneuvers, including hovering, takeoff, and transitions. During the session, light drizzle began to accumulate on the external windscreens, significantly obscuring the pilots' vision. To clear the moisture, the instructor decided to fly a circuit of the airfield.
While transitioning from a hover, the instructor was closely monitoring the position of another helicopter in the vicinity to ensure a safe takeoff path. During this period of intense monitoring, the instructor actively managed the student's control inputs. Specifically, the instructor resisted the student's attempts to increase the collective pitch and may have even lowered it. This action was intended to prevent the aircraft from entering the dangerous height-velocity envelope 'avoid area'.
As the aircraft accelerated and achieved translational lift, the landing gear struck the ground, resulting in a crash. The impact caused extensive damage to the fuselage, main rotor blades, and landing gear. The student sustained one minor injury, while the instructor remained uninjured. Following the impact, the instructor identified a fuel leak and moved both occupants away from the wreckage.
The investigation
The investigation established that the instructor's primary focus was on maintaining separation from another aircraft and managing the student's flight path to avoid a specific aerodynamic hazard. The investigation also noted that the instructor's intervention with the collective control lever directly contributed to the descent that led to the ground impact. Furthermore, it was noted that because the training area operated without the need for routine radio calls, air traffic controllers were initially unaware of the accident.
Findings
- The instructor's attempt to prevent the aircraft from entering the height-velocity envelope 'avoid area' led to the collective pitch being restricted or lowered.
- The instructor's management of the collective control lever caused the aircraft to descend into the ground.
- Visibility was impaired by light drizzle accumulating on the outside of the windscreens.
- The instructor was simultaneously monitoring the flight controls and the proximity of another aircraft.