Airworthiness Directive · Amendment 39-10873 · Pratt & Whitney PW4000 Series Turbofan Engines
Pratt & Whitney PW4000 Series Turbofan Engines
Pratt & Whitney (PW) Model PW4152, PW4056, PW4156, PW4256, PW4052, PW4158, PW4060, PW4160, PW4460, PW4050, PW4060A, PW4156A, PW4062, PW4462, PW4060C, and PW4650 turbofan engines, not incorporating at least one of the modifications described in the PW service bulletins (SBs) and listed in items (1) through (6), excluding those engines having a (-3) identifier next to the engine model number on the engine data plate. These engines are installed on but not limited to Boeing 767 and 747 series aircraft, McDonnell Douglas MD-11 series aircraft, and Airbus A310 and A300-600 series aircraft. (1) PW4ENG 72-484, Revision 3, dated July 1, 1997, or earlier revisions, PW4ENG 72-486, Revision 1, dated November 23, 1994, or original issue. (2) PW4ENG 72-484, Revision 3, dated July 1, 1997, or earlier revisions, PW4ENG 72-575, Revision 1, dated June 30, 1997, or original issue, PW4ENG 72-486, Revision 1, dated November 23, 1994, or original issue. (3) PW4ENG 72-514, Revision 1, dated August 2, 1996, or original issue. (4) PW4ENG 72-490, Revision 1, dated August 2, 1994, or original issue. (5) PW4ENG 72-504, Revision 1, dated May 9, 1995, or original issue. (6) PW4ENG 72-572, dated June 16, 1995.
This amendment adopts a new airworthiness directive (AD), applicable to certain Pratt & Whitney (PW) PW4000 series turbofan engines not incorporating modifications described in certain PW service bulletins listed in the applicability section, that requires high pressure compressor (HPC) blade tip grinding of the rotor assembly, installation of aluminum oxide coated HPC blade tips in stages 9 through 12, modification of HPC 8th through 14th stage stators, incorporation of 1st stage high pressure turbine (HPT) vanes with increased airflow area which also requires additional HPT hardware modifications, and incorporation of HPC 13th-15th stage zirconium oxide blade tips. This amendment is prompted by reports of HPC surge caused by excessive HPC rear stage rotor-to-case clearance. The actions specified by this AD are intended to prevent HPC surge, which can result in engine power loss at a critical phase of flight such as takeoff or climb.
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.
