What happened
On 26 October 2011, a Guimbal Cabri G2, registration G-UIMB, was performing a private flight near Cotswold Airport (Kemble). The pilot was executing an approach to land on Runway 26, with winds recorded at 17 knots from 200°.
After turning onto finals to the south of the runway, the helicopter passed the airfield boundary and turned into the wind. As the aircraft levelled off at an altitude of approximately 5 feet, it began to yaw gently to the left. Despite the pilot applying right yaw pedal, the yaw rate accelerated rapidly. In an attempt to maintain clearance from the ground, the pilot increased the collective pitch. This action further intensified the yawing motion, causing the aircraft to rotate through three to six full revolutions. During this period, the pilot verified that the correct pedal inputs were being applied. During the rotation, the engine ceased operation. The pilot attempted to cushion the landing, but the aircraft struck the ground heavily.
There were no injuries to the pilot or the passenger. The impact caused significant damage to the skid bows, skid bow mountings, and the empennage, including a partial fracture of the tailboom forward of the horizontal stabiliser.
The investigation
Investigators examined the aircraft and the circumstances leading to the loss of control. Post-impact inspections of the engine revealed no mechanical anomalies prior to the event. The investigation focused on the relationship between the high yaw rate and the engine's performance.