Airworthiness Directive · Amendment 39-14002 · Pratt & Whitney JT9D-59A, -70A, -7Q, and -7Q3 Turbofan Engines
Pratt & Whitney JT9D-59A, -70A, -7Q, and -7Q3 Turbofan Engines
This AD applies to Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, and -7Q3 turbofan engines with high pressure turbine (HPT) second stage airseal, part number (P/N) 5002537-01, 788945, 753187, or 807410, installed. These engines are installed on, but not limited to, Airbus Industrie A300 series, Boeing 747 series, and McDonnell Douglas DC-10 series airplanes.
The FAA is superseding an existing airworthiness directive (AD) for Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, and -7Q3 turbofan engines. That AD currently requires fluorescent penetrant inspection (FPI) of high pressure turbine (HPT) second stage airseals, part numbers (P/Ns) 5002537-01, 788945, 753187, and 807410, knife-edges for cracks, each time the engine's HPT second stage airseal is accessible. This AD requires replacing each existing HPT second stage airseal with an improved design HPT second stage airseal and modifying the 2nd stage HPT vane cluster assembly and 1st stage retaining blade HPT plate assembly at next piece-part exposure, but no later than five years after the effective date of this AD. These actions are considered terminating action to the repetitive inspections required by AD 2002- 10-07. This AD results from the manufacturer introducing an improved design HPT second stage airseal and modifications to increase cooling. We are issuing this AD to prevent failure of the HPT second stage airseal due to cracks in the knife-edges, which if not detected, could result in uncontained engine failure and damage to the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
At the next piece-part exposure, but no later than five years after the effective date of this AD, replace the HPT second stage airseal with a P/N HPT second stage airseal that is not listed in this AD, and modify the 2nd stage HPT vane cluster assembly and 1st stage retaining blade HPT plate assembly. Use the Accomplishment Instructions of PW Service Bulletin No. JT9D 6454, Revision 3, dated November 9, 2004, to do this.
For the purposes of this AD, piece-part exposure means the HPT second stage airseal disk is considered completely disassembled, when done in accordance with the disassembly instructions in the engine manufacturer's, or other FAA-approved engine manual.
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.
