EASA has issued an emergency airworthiness directive mandating inspection of the swashplate bearing on Airbus H160 helicopters before any cleaning of the bearing, every 15 flight hours, or every seven days, whichever comes first. The agency took the action following reports of “premature in-service degradation” of the bearing. Failure of the bearing could lead to reduced control of the helicopter, as swashplates are a key helicopter directional control component.
According to EASA, the use of the wrong grease or the mixing of incompatible greases might have initiated the degradation. The agency also pointed out that vibration health monitoring (VHM) aboard the helicopter has been as effective as other inspections in detecting early degradation of the bearing, but the reliability of VHM has not been sufficiently demonstrated “unless additional precautions are taken.”
Airbus Helicopters has provided operators with a related emergency alert service bulletin (Emergency ASB H160-B 62-32-0001) to provide inspection instructions and ensure VHM data is analyzed on a regular basis. If any functional discrepancy is detected, the entire main rotor mast assembly must be replaced per the ASB.
