Airworthiness Directives; General Electric Company CF6-80A1/A3 and CF6-80C2A PMC Series Turbofan Engines

This amendment adopts a new airworthiness directive (AD), that is applicable to General Electric Company (GE) CF6-80A1/A3 and CF6- 80C2A PMC series turbofan engines. This amendment requires performing either a directional pilot valve (DPV) pressure switch moisture purge procedure and an operational check of the fan reverser or replacing the DPV assembly with a serviceable assembly and performing an operational check of the fan reverser. Thereafter, this AD requires one of these actions on a repetitive basis. This amendment is prompted by a review of fan reverser safety analyses resulting from the discovery of an undetectable failure mode of the DPV pressure switch on certain GE CF6- 80C2A and CF6-80A1/A3 engine models. The actions specified by this AD are intended to prevent inadvertent fan reverser deployment, which, if it occurred in-flight, could result in loss of control of the airplane.