EASA 2019-0108

Requires replacement of the main gearbox (MGB) particle detectors.  This AD is prompted by an EC 225 helicopter accident investigation that revealed the involvement of a failure of a second stage planet gear of the MGB. Following a review of design similarities, it was determined that such an event might conceivably also occur on SA 330 J helicopters. This condition, if not detected and corrected, could lead to loss of control of the helicopter. As a protective measure, Airbus Helicopters determined that more effective monitoring of oil debris could effectively establish an acceptable level of safety with the installation of an improved, elongated MGB particle detector.