What happened
On 27 October 2018, a Leonardo AW169, registration G-VSKP, was involved in an accident at the King Power Stadium in Leicester. During the flight, the aircraft experienced a sudden and catastrophic loss of tail rotor control. The resulting loss of directional stability led to the helicopter crashing at the stadium site. There were no fatalities reported, though the aircraft sustained significant damage during the impact.
The investigation
The AAIB investigation focused on the mechanical integrity of the tail rotor system, specifically examining the duplex bearing. Investigators performed an in-depth forensic laboratory analysis of the wreckage and conducted extensive engineering tests. This included an endurance rig test requested by the investigators, as well as subsequent testing by the manufacturer. The investigation also reviewed the design and certification processes for the tail rotor's non-structural critical parts, looking at how load spectrums are calculated and how the bearing's life is managed.
Findings
- The primary cause of the accident was the failure of the tail rotor duplex bearing.
- The investigation established that the bearing failure was linked to complex loading conditions and the way design load spectrums were calculated for non-structural critical parts.
- The failure of the bearing led directly to the loss of tail rotor control and the subsequent loss of aircraft stability.
- The investigation noted that the design load spectrums for such parts must account for the highest individual operating loads and the duration of exposure to those loads with an appropriate safety margin.