WASHINGTON—A material defect affecting PW1100G-JM-series high pressure turbine disks linked to a March 2020 uncontained engine failure may be more widespread than originally believed, prompting the FAA to propose mandating inspections recommended by Pratt & Whitney.
The latest batch of affected high pressure turbine (HPT) 1st and 2nd stage disks may be installed on as many as 189 engines on Airbus A320neo-family aircraft in the U.S.-registered fleet, an FAA draft directive set for publication March 24 shows. Previous analysis by Pratt & Whitney found the issue affected fewer than 10 U.S.-registered V2500s and PW1100G-JMs. Both subsets are covered by existing mandates.
Pratt discovered the issue while investigating the uncontained failure of an International Aero Engines V2500 powering a Vietnam Airlines A321-200 on March 18, 2020, that sent debris into the engine cowling and prompted an aborted takeoff. Investigators soon discovered an HPT 1st stage disk failed, prompting the FAA to issue an emergency airworthiness directive on March 21, 2020, ordering the removal of certain disks from service.
Pratt determined the issue was “due to an undetected subsurface material defect in an HPT disk that may affect the life of the part,” the FAA explained in its emergency directive. It did not provide details about the defect.
In June 2021, Pratt “expanded its root cause analysis to include a review of records for all other IAE and PW engines that contain parts of similar material,” the FAA said in a subsequent mandate. The engine-maker discovered a few more at-risk disks, including three in the U.S., that should be removed. The FAA mandated that recommendation in September 2021.
Following that mandate, Pratt “identified another subpopulation of HPT 1st-stage disks and HPT 2nd-stage disks that require inspection and possible removal from service,” the FAA said in the new draft directive.
The latest mandate, which covers all 10 certified PW1100G-JM models, stops short of ordering affected parts removed. Instead, the FAA proposes an ultrasonic inspection (USI) of specific HPT 1st and 2nd stage disks at the next shop visit. Disks that do not pass the USI should be replaced before further flight, at a cost of about $170,000 per part, the FAA draft directive said.
It is not clear how many engines may be affected in the global fleet. Pratt did not immediately respond to an Aviation Week inquiry.
Pratt’s analysis also found a small number of PW1500G and PW1900G engines found on A220s and Embraer E2s, respectively, with potentially affected disks. The FAA in January mandated their removal, including from up to eight engines in the U.S. fleet.
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