The FAA today issued AD 2007-17-21, which affects Pratt & Whitney JT9D-7R4 series turbofan engines and will become effective Sept. 28.
The AD requires removing reduced cooling flow 2nd stage high pressure turbine (HPT) vane assemblies, part numbers (P/Ns) 797282, 796972, 800082, 800072, 803182, 803282 and 822582, installed in 2nd stage HPT vane cluster assemblies P/Ns 797592, 797372, 799872, 799782, and 822572, in addition to a visual and a fluorescent penetrant inspection (FPI) of the 2nd stage HPT air seal assembly, P/N 815097. The FAA estimates the AD will affect 85 PW JT9D-7R4 series turbofan engines installed on airplanes in the U.S. registry. It estimates a material cost of $6,700 and 65.5 hours of labor at $80 per work-hour, for a total cost of compliance per engine of $11,940. The AD intends to prevent uncontained failure of the 2nd stage HPT air seal assembly, potentially leading to engine in-flight shutdown and damage to the airplane.