Airworthiness Directive · Amendment 39-21351 · Turbine section
Pratt & Whitney Division Turbofan Engines
This AD applies to all Pratt & Whitney Division (PW) PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model turbofan engines that have 3rd stage low-pressure turbine (LPT) duct segments, part number (P/N) 50N434-01 or P/N 50N450-01 installed, and have the Talon IIB outer combustion chamber assembly, P/N 51J500 or P/N 51J381, installed.
The FAA is adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model turbofan engines with a certain outer combustion chamber assembly and 3rd stage low-pressure turbine (LPT) duct segments installed. This AD was prompted by reports of damaged or failed 3rd stage LPT duct segments on PW engines with the Talon IIB outer combustion chamber assembly configuration installed. This AD requires removing and replacing certain 3rd stage LPT duct segments. The FAA is issuing this AD to address the unsafe condition on these products.
At every engine shop visit after the effective date of this AD, remove from service the 3rd stage LPT duct segments, P/N 50N434-01 and P/N 50N450-01, and replace them with parts with zero flight cycles.
Removal of the 3rd stage LPT duct segments, P/N 50N434-01 and P/N 50N450-01, and their replacement with parts having P/Ns other than P/N 50N434-01 and P/N 50N450-01, constitutes terminating action for the repetitive replacement required by paragraph (g) of this AD.
For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges (lettered flanges). The separation of engine flanges solely for the purpose of transportation without subsequent engine maintenance does not constitute an engine shop visit.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
