Federal Register #2026-21298

FAA proposal for inspections and replacement of specified Pratt & Whitney RTX engine components

The Federal Aviation Administration proposes revised safety requirements for specified Pratt & Whitney RTX aircraft engines; this is a regulatory proposal, not a purchase request. - Government buyer: U.S. Department of Transportation, Federal Aviation Administration (FAA); no sub-office is identified. - OEM: Pratt & Whitney RTX Corporation, manufacturer of the affected PW engine models and the source of referenced service instructions. - Affected engine models: PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3. - Proposed requirements: - Repetitive angle ultrasonic inspections of specified high-pressure compressor (HPC) and turbine components for cracks. - Remove and replace a component with a crack indication before further flight. - Remove and replace certain serial-numbered high-pressure turbine (HPT) 1st-stage air seals at the next piece-part opportunity. - The affected components may qualify for installation when accompanied by certificates of conformance demonstrating compliance with the applicable Pratt & Whitney instructions. - Affected component part numbers: - HPC 15th-stage disks: 51S115, 51S315, 55H615, 56H015. - Front turbine hubs: 55L801, 55L901. - HPT 1st-stage air seals: 50L663, 50L959. - HPT 2nd-stage hubs: 53L202, 53L402, 54L802. - The proposal addresses an omitted part number and a mismatch involving an optional terminating action in the existing directive.

Description

The Federal Aviation Administration proposes to supersede Airworthiness Directive 2026-09-02 for certain Pratt & Whitney RTX Corporation PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines. The proposed directive requires repetitive angle ultrasonic scan inspections of specified compressor and turbine components for crack indications, with removal and replacement when necessary. It also requires removal and replacement of certain HPT 1st-stage air seals for specified serial numbers. The FAA identifies an omitted part number and an incorrectly matched optional terminating action in the existing directive as reasons for the proposal; comments are due December 3, 2026.

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