Airworthiness Directive · Amendment 39-22084 · Turbine section
Pratt & Whitney Division Turbofan Engines
This AD applies to Pratt & Whitney Division (PW) PW4062 model turbofan engines with an installed low-pressure turbine (LPT) stage 5 air seal, part number (P/N) 50N324, having a serial number (S/N) listed in Table 1 to paragraph (c) of this AD, installed.
The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney Division (PW) PW4062 model turbofan engines. This AD was prompted by a report of a manufacturing quality escape due to insufficient cooling of the low-pressure turbine (LPT) stage 5 air seal resulting in a reduction of the low-cycle fatigue (LCF) life limit. This AD requires removal and replacement of the LPT stage 5 air seal with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.
At the next piece-part exposure, or before the LPT stage 5 air seal accumulates 8,240 cycles since new, whichever occurs first after the effective date of this AD, remove the LPT stage 5 air seal from service and replace it with a part eligible for installation.
(1) For the purpose of this AD, “piece-part exposure” is when an LPT stage 5 air seal has been disassembled from the engine.
(2) For the purpose of this AD, a “part eligible for installation” is an LPT stage 5 air seal, P/N 50N324, with an S/N not listed in Table 1 to Paragraph (c) of this AD.
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.
