Airworthiness Directive · Amendment 39-11220 · Pratt & Whitney PW4000 Series Turbofan Engines
Pratt & Whitney PW4000 Series Turbofan Engines
Pratt & Whitney Model PW4056, PW4152, PW4156A, PW4164, PW4168, and PW4460 turbofan engines, with 4th stage low pressure turbine (LPT) disks, part number (P/N) 50N924, serial numbers (S/Ns) CLDL BX2061, CLDL BX6620, CLDL BX2054, CLDL BX2055, CLDL BX6596, CLDL BX2059, CLDL BX2060, CLDL BX6600, CLDL BX6597, CLDL BX6599, CLDL BX6601, CLDL BX6598, CLDL BX6604, CLDL BX6605, CLDL BX6602, CLDL BX6609, CLDL BX6607, CLDL BX6612, CLDL BX6611, CLDL BX6610, CLDL BX6608, CLDL BX6606, CLDL BX6615, CLDL BX6616, CLDL BX6619, CLDL BX2058, and CLDL BX6603 installed. These engines are installed on but not limited to Airbus Industrie A330, Boeing 747, and McDonnell Douglas MD-11 series aircraft.
This amendment adopts a new airworthiness directive (AD), applicable to certain Pratt & Whitney PW4000 series turbofan engines, that reduces life limits of certain 4th stage low pressure turbine (LPT) disks. It also allows the original life limits of the disks to be restored if reoperation is performed to incorporate the original slotted cooling hole configuration. This amendment is prompted by reports that a change of a cooling hole geometry, which was introduced in the design of certain 4th stage LPT disks, inadvertently caused a reduction on the cooling air flow to the disk and an increased level of stress. The actions specified by this AD are intended to prevent an uncontained disk failure and 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.
