FAA Clarifies Engine Inspections After Missing a Pratt & Whitney Part Number
Published Date: 10/19/2026
Proposed Rule
Summary
The FAA wants to update safety rules for certain Pratt & Whitney RTX engines to fix a missed part number and clarify inspection steps. If you own or operate these engines, you’ll need to keep checking key parts for cracks and replace them if needed to keep flying safe. Comments on this update are open until December 3, 2026, so get involved before then!
Analyzed Economic Effects
4 provisions identified: 1 benefits, 3 costs, 0 mixed.
Required repetitive inspections of key parts
If you own or operate the listed Pratt & Whitney RTX PW4074/PW4077/PW4084D/PW4090-series engines, the FAA proposes repetitive angle ultrasonic scan inspections (AUSIs) of the HPC 15th-stage disks, front turbine hubs, HPT 1st-stage air seals, and HPT 2nd-stage hubs for crack indications. The FAA estimates this proposed AD would affect 124 engines on U.S. registry; the agency lists inspection labor costs of $340 for the HPC 15th-stage disk inspection and $425 for each of the other part inspections, and gives total U.S. operator inspection cost estimates of $42,160 and $52,700 for those inspection types.
Mandatory replacement for specific air‑seal serial numbers
For HPT 1st-stage air seals with the serial numbers listed in Table 1 to paragraph (g)(1) of the AD, you must remove the HPT 1st-stage air seal at the next piece part opportunity and replace it with a part eligible for installation. The FAA estimates 6 engines will require replacement of these HPT 1st-stage air seals and provides a replacement cost per product of about $763,085 and a total U.S. operators cost of $4,578,510 for those six replacements.
Optional terminating action via ALS revision
You may avoid the repetitive AUSI requirements in paragraphs (g)(2) and (g)(3) by revising the Airworthiness Limitations Section (ALS) of the engine manual and your approved maintenance/inspection program to incorporate the information in figure 1 to paragraph (i) of this AD; doing so constitutes terminating action for those required inspections. The AD identifies this ALS revision as the optional terminating action.
Adds HPT 2nd‑stage hub P/N 53L402 to coverage
The proposed AD adds HPT 2nd-stage hub part number (P/N) 53L402 to the list of parts covered by the inspection requirements. If you have HPT 2nd-stage hubs with P/N 53L402, those parts are now explicitly subject to the AUSI and replacement requirements in this proposed AD.
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Key Dates
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