Summary
The FAA proposes to adopt a new airworthiness directive (AD) for Leonardo S.p.a. (Leonardo) Model AB139 and AW139 helicopters. This proposed AD would require removing certain main gearbox (MGB) input modules from service. This proposed AD was prompted by the discovery that a batch of duplex bearings, which are installed on the MGB input modules, are defective. The actions of this proposed AD are intended to address an unsafe condition on these products.