What happened
On 3 February 2025, a Robinson R22 Beta helicopter, registration G-KKRN, was conducting a training flight near Wokingham, Berkshire. The flight was part of a conversion course for a pilot already qualified on the Guimbal Cabri G2. The syllabus for the day included engine-out training and practice autorotations.
While the aircraft was positioning to rejoin the circuit at White Waltham, the trainee pilot was instructed to descend. To prepare for the descent, the trainee attempted to activate the carburettor heating. However, the trainee mistakenly manipulated the fuel mixture control instead. This action caused the engine to shut down immediately.
The instructor took control and established an autorotation from approximately 800 ft agl. Due to the low altitude, there was insufficient time to attempt an engine restart. The instructor selected a ploughed field for landing to avoid nearby trees and powerlines. As the helicopter touched down, the skids dug into the soil, causing the aircraft to tip forward and roll. During the impact, the main rotors struck the rear empennage, causing it to detach. There were no injuries to the two crew members on board.
The investigation
The investigation examined the cockpit configuration and the sequence of control inputs. It was noted that the mixture control is positioned directly in front of the carburettor heating control. While a plastic guard is used to prevent accidental movement of the mixture control, it is possible to dislodge this guard by applying upward pressure.
The investigation also reviewed the manufacturer's history regarding this specific risk. The potential for misidentifying these controls was first documented by the manufacturer in 1981. The investigation found that the instructor had briefed the trainee on the correct use of the controls and the risks of carburettor icing prior to the flight.