Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to Pratt & Whitney (PW) PW4000 series turbofan engines. This action requires initial and repetitive inspections of the aft cascade support frame assembly of thrust reverser for cracks, and replacement, if necessary, with serviceable parts; or lockout of the thrust reversers. This amendment is prompted by reports of aft cascade support frame assembly failures. The actions specified in this AD are intended to prevent aft cascade support frame assembly failure due to cracks, which can result in thrust reverser hardware liberation and ejection from the aircraft during thrust reverser operation, which can contaminate the runway with debris, causing an operational hazard to other aircraft during takeoff and landing.