AAIB report Guimbal Cabri G2 helicopter, loss of control during hover


While conducting a simulated engine failure from the hover, the helicopter yawed rapidly to the left. Despite the actions of the pilots the helicopter continued to yaw rapidly and control was not recovered. The helicopter was seen to climb while spinning before descending rapidly and contacting the ground, sustaining severe damage.

The investigation found that the accident was probably initiated by a premature application of the left yaw pedal and raising the collective lever, before the throttle was fully closed during a simulated engine failure exercise. There remained sufficient space within the cabin for the occupants to survive the accident and to allow the first responders to extricate them swiftly without risking further injury. The flexible fuel tank liner had not been compromised and there was no post-crash fire. A combination of the energy absorbing seat system and the destruction of the composite fuselage absorbed impact energy such that both occupants survived with injuries that were serious but not life-threatening.

The helicopter manufacturer has subsequently issued two Service Letters to prevent reoccurrence. One is on throttle management during simulated engine failure. One is on controllability in yaw at low rotor speed.

Read the report.

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