What happened
On 11 November 2004, a student pilot was conducting a solo cross-country navigation exercise in a Robinson R22 Beta, registration G-TGRR. The flight was part of a training program between Shobdon and Wellesbourne. Due to deteriorating weather conditions, the pilot's instructor decided to fly in a separate helicopter to lead the student back to Shobdon in a loose formation to assist with navigation.
During the return leg, the student reported difficulty maintaining visual contact with the lead aircraft. Shortly after, the student radioed that he could no longer see the instructor's helicopter, stating, "I can't see a thing." Witnesses on the ground observed the helicopter flying level before it suddenly pitched upward, lost all forward motion, and then pitched nose-down into a vertical descent. The aircraft struck a ploughed field near Bishopton, resulting in 1 fatality.
The investigation
The AAIB investigation examined the wreckage and the engine components. While there was no evidence of a mechanical failure that would have caused the engine to stop, investigators found that the engine was not rotating at the moment of impact. The investigation also focused on the cockpit controls, noting that the carburettor heat control was positioned toward the maximum hot air setting, though the impact may have altered this position.
Investigators also reviewed the meteorological conditions, which included drizzle, mist, and a low cloud base of approximately 800 to 1,200 feet. Furthermore, the investigation looked into the student's training, noting that while he was a qualified student pilot, he had received no formal training in formation flying, which was the method being used to guide him through the poor visibility.
Findings
- The student pilot was attempting to fly in a loose formation despite having no prior training in this demanding task.
- The weather conditions during the flight were below the training organisation's established minima for solo flight.
- The pilot was operating in a degraded visual environment, which significantly increased his workload and reduced his ability to monitor critical engine parameters.
- The helicopter likely encountered severe carburettor icing, which either significantly reduced engine power or caused the engine to stop.
- Due to the high stress of following the lead aircraft in low visibility, the pilot was unable to react quickly enough to prevent a critical drop in rotor RPM, leading to a rotor stall and an unrecoverable descent.