What happened
On 20 June 2022, a Guimbal Cabri G2, registration G-CJEK, was conducting a private flight near Burton in Lonsdale, North Yorkshire. The flight, intended as a local experience for a passenger, departed from a private site and traveled around the Lake District before returning to the departure point.
As the helicopter approached the landing site, CCTV and witness accounts indicate it performed a controlled left turn, climbing from approximately 70 ft to 130 ft. Following this, the aircraft entered an uncontrolled left yaw. Witnesses reported hearing a loud noise, after which the helicopter's nose dropped, and it descended rapidly into a tree-lined gully. The impact was followed by an intense post-crash fire that destroyed the fuselage. Both the pilot and the passenger sustained fatal injuries.
The investigation
The AAIB examined the wreckage, which was recovered to Farnborough. While the intense fire destroyed many aluminium components, making it impossible to confirm the continuity of the yaw control system, investigators found that the engine was providing power to the rotor system at the time of impact. The tail rotor drive shaft showed evidence of failure due to torsional overload and bending, likely caused by the aircraft striking the trees.
Investigators also reviewed manufacturer Service Letters (SL) regarding the Cabri G2's unique handling characteristics, specifically related to its Fenestron tail rotor. The investigation considered several scenarios, including mechanical failure, pilot handling, inadvertent passenger input, and medical incapacitation. While the pilot had significant experience, the post-mortem report noted risk factors that could suggest a sudden medical event, though no acute event was confirmed.
Findings
- The aircraft was within weight and balance limits and had been regularly maintained.
- The investigation could not rule out a mechanical failure involving the tail rotor or pitch control due to fire damage.
- The possibility of an inadvertent control input by the passenger could not be dismissed.
- The pilot's potential medical incapacitation remained a possible factor.
- The aircraft's specific handling characteristics during low rotor RPM or certain wind conditions could have contributed to the loss of control.