Airworthiness Directives; General Electric Company Turbofan Engines
We are adopting a new airworthiness directive (AD) for all General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines. This emergency AD was sent previously to all known U.S. owners and operators of these engines. This AD prohibits operation of an airplane with affected transfer gearbox assemblies (TGBs) installed on both engines five days after the effective date of this AD. This AD was prompted by reports of two failures of TGBs which resulted in in-flight shutdowns (IFSDs). We are issuing this AD to prevent additional IFSDs of one or more engines, loss of thrust control, and damage to the airplane.