AD FAA-2020-0390

The FAA is adopting a new airworthiness directive (AD) for PZL Swidnik S.A. (PZL) Model PZL W-3A helicopters. This AD requires inspecting the main gearbox (MGB) bolts and washers to determine if they are properly locked and, depending on the inspection outcome, removing the engine, removing certain bolts from service, and performing more in-depth inspections; and depending on the outcome of those inspections, replacing the graphite seal assembly or removing it from service. Finally, this AD prohibits installing any affected MGB on a helicopter unless it has met the requirements of this AD. This AD was prompted by reports that the bolts securing the input quill and graphite seal assembly of the MGB were not properly locked. The actions of this AD are intended to address an unsafe condition on these products.