Airworthiness Directive · Amendment 39-18307 · Pratt & Whitney Division Turbofan Engines
Pratt & Whitney Division Turbofan Engines
This AD applies to:
(1) All Pratt & Whitney Division PW4164, PW4168, PW4168A, PW4164C, PW4164C/B, PW4164-1D, PW4168-1D, PW4168A-1D, PW4170, PW4164C-1D, and PW4164C/B-1D turbofan engines with a low-pressure turbine (LPT) 4th stage inner air seal (IAS), part number (P/N) 51N038, installed.
(2) All PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650 turbofan engines including models with a “-3” suffix with an LPT 4th stage IAS, P/N 51N038, installed.
We are adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4164, PW4168, PW4168A, PW4164C, PW4164C/B, PW4164-1D, PW4168-1D, PW4168A-1D, PW4170, PW4164C-1D, PW4164C/B-1D, PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650 turbofan engines including models with a "-3" suffix with a low-pressure turbine (LPT) 4th stage inner air seal (IAS), part number (P/N) 51N038, installed. This AD was prompted by the discovery, during routine overhaul of the LPT, of cracks in the barrel section of the LPT 4th stage IAS. This AD requires removal of the LPT 4th stage IAS, P/N 51N038, according to a prescribed schedule. We are issuing this AD to prevent failure of the LPT 4th stage IAS, which could lead to an uncontained IAS release, damage to the engine, and damage to the airplane.
(1) At each LPT overhaul after the effective date of this AD, remove from service the LPT 4th stage IAS, P/N 51N038.
(2) At each engine shop visit after the effective date of this AD, remove from service the LPT 4th stage IAS, P/N 51N038, if it has more than 10,900 cycles since new.
(1) Do not install any LPT 4th stage IAS, P/N 51N038, with more than 0 flight cycles on any engine listed in paragraph (c)(1) of this AD.
(2) Do not install on any engine listed in paragraphs (c)(2) of this AD, any LPT 4th stage IAS, P/N 51N038, which was previously installed on any engine listed in paragraph (c)(1) of this AD.
For the purposes of this AD:
(1) An LPT overhaul is defined as when all disks in the rotor are removed from the engine and the blades are removed.
(2) 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.
