Airworthiness Directives; Pratt & Whitney RTX Corporation (Type Certificate Previously Held by Pratt & Whitney Division United Technologies Corporation) Engines
Key claim: The FAA is issuing a new airworthiness directive requiring repetitive ultrasonic inspections and potential replacement of high-pressure compressor and turbine components on certain Pratt & Whitney PW4074/4077/4084D/4090 engines to address unsafe conditions identified after an HPC rotor separation event.
Abstract
(Rule · Transportation Department, Federal Aviation Administration) The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney RTX Corporation (PW) Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines. This AD was prompted by an analysis of an event involving an International Aero Engines, LLC (IAE LLC) Model PW1127GA-JM engine, which experienced a high-pressure compressor (HPC) 7th-stage integrally bladed rotor (IBR- 7) separation that resulted in an aborted takeoff. This AD requires repetitive angle ultrasonic scan inspections (AUSIs) of the HPC 15th- stage disks, front turbine hubs, high pressure turbine (HPT) 1st-stage air seals, and HPT 2nd-stage hubs for crack indications, and removal from service and replacement if necessary, and for certain serial numbers, removal from service and replacement of the HPT 1st-stage air seal. The FAA is issuing this AD to address the unsafe condition on these products.
Why this matters
Repetitive ultrasonic inspections and part replacements on widely used PW4000-series high-thrust engines directly affect the operational availability and maintenance burden of long-haul twin-engine fleets (notably Boeing 777 and 767 variants). The action follows a specific HPC rotor separation event, reinforcing the FAA’s pattern of using ADs to contain uncontained-failure risks in mature engine populations.