Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This AD requires inspecting the main gearbox (MGB) for a crack. This AD is prompted by a crack in the cored passage of the MGB housing, which may be indicated by oil on the housing. These actions are intended to detect a crack in the MGB housing, which could result in loss of oil, failure of the MGB, and subsequent loss of control of the helicopter.