AAIB investigation to Sikorsky S-92A, G-CIJC
Excessive vibration due to main rotor damper component failure, Aberdeen Airport, 5 March 2026
The pilot detected higher than normal vibration during a scheduled flight and following a Health and Usage Monitoring Systems (HUMS) analysis, the helicopter was removed from service. The main rotor hub was inspected and part of the barrel nut which retained the outboard bearing of the main rotor damper to the piston was found to be missing. As the missing item, known as the cradle, was not available, no assessment could be made to determine why the part had failed. The helicopter manufacturer was aware of four other similar events in which part of the barrel nut was missing, but had previously determined, through its assessment of a more extreme failure case, that this had no effect on the continued safe flight and landing of the helicopter.
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