Airworthiness Directive · Amendment 39-9721 · Pratt & Whitney JT9D-7R4 Series Turbofan Engines
Pratt & Whitney JT9D-7R4 Series Turbofan Engines
Pratt & Whitney (PW) JT9D-7R4 series turbofan engines, installed on but not limited to Airbus A300 and A310 series, and Boeing 747 and 767 series aircraft. Note: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney (PW) JT9D-7R4 series turbofan engines, that requires replacement of 3rd, 4th, and 5th stage low pressure turbine (LPT) vane retention bolts and nuts, the removal of the 5th stage vane configuration which includes an electro-discharge machined (EDM) slot and replacement with a cast slot configuration, and prohibits the use of uncured anti-gallant compound on vane retention hardware. This amendment is prompted by reports of LPT failures that resulted in uncontained engine failures. The actions specified by this AD are intended to prevent LPT vane failures, which can result in uncontained engine failure, fire, and possible damage to the aircraft.
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.
