Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain P&W PW4000 series turbofan engines. This AD was prompted by reports of 3rd and 4th stage vane fractures in the low-pressure turbine (LPT) of certain PW4000-94" and PW4000-100" turbofan engines. This AD requires dimensional inspections of LPT 3rd stage vanes and the rear turbine case, inspection of LPT 4th stage vanes at the next LPT overhaul and removal of vanes with non-conforming airfoil fillet radii and vanes with more than one strip and recoat repair. This AD also requires disassembly and reassembly of the 2nd stage high-pressure turbine (HPT) rotor and 3rd stage LPT rotor at the next HPT and LPT overhauls. We are issuing this AD to prevent 3rd and 4th stage vane fractures in the LPT, damage to the LPT rotor, uncontained engine failure, and damage to the airplane.