In a response to reports of "premature in-service degradation" of swashplate bearings on Airbus H160 helicopters, the European Union Aviation Safety Agency (EASA) has issued an emergency airworthiness directive, raising the stakes for safety in the aviation community.
The AD from EASA is mandating inspections before any cleaning of the bearing, the directive prescribes a thorough examination every 15 flight hours or at least every seven days, prioritizing the shorter interval. The urgency arises from the potential consequences of bearing failure, which could result in compromised control of the helicopter, given the critical role that swashplates play in the directional control of the aircraft.
EASA highlights the possibility that the degradation may have been triggered by the use of incorrect grease or the mixing of incompatible greases. The agency also emphasizes the role of vibration health monitoring (VHM) aboard the helicopter, noting its effectiveness in early detection of bearing degradation. However, EASA cautions that the insufficiently proven reliability of VHM requires that additional precautions be taken.
In response to the directive, Airbus Helicopters has swiftly provided operators with an emergency alert service bulletin (Emergency ASB H160-B 62-32-0001). This bulletin not only furnishes operators with detailed inspection instructions but also underscores the importance of regularly analyzing VHM data. Significantly, if any functional discrepancy is identified, operators are mandated to replace the entire main rotor mast assembly in accordance with the ASB.
The link to download the EASA AD can be found here: https://ad.easa.europa.eu/ad/2023-0222-E
