What happened
On 11 March 2007, a Robinson R44 Raven, registration G-EKKO, was performing a private flight near Tupton, Chesterfield. The aircraft was returning to its base after a training exercise at Sandtoft Airfield, with the pilot acting as both instructor and handling pilot. The intended destination was a private landing site at Hollis Farm.
As the pilot approached the farmyard from the east, the flight plan involved a 180-degree turn followed by a hover-taxi across a sloping field toward the farm buildings. During this maneuver, while the aircraft was taxiing down the slope, the pilot experienced sudden, intense vibrations and shaking. The pilot responded by immediately landing the aircraft and shutting down the engine. There were no injuries to the two occupants, who were able to exit the helicopter without difficulty.
The investigation
AAIB investigators examined the wreckage at the site, noting that the helicopter had come to rest at the bottom of the field. The investigation revealed that the tail rotor gearbox was missing and the empennage was nearly detached from the tail boom. Specifically, the lower stabilizer showed damage consistent with being struck by a rotating tail rotor blade.
While the tail rotor debris had been moved prior to the official examination, preventing the identification of specific ground impact marks, the physical state of the wreckage was telling. The investigation focused on the structural integrity of the tail rotor assembly and the mechanics of the component failure.