EASA AD US-2022-07-13
Engine Oil - Air/Oil Heat Exchanger - Inspection / Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2022-07-13 addresses Pratt & Whitney Division turbofan engines models PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3. This directive mandates inspection and possible replacement of the air/oil heat exchanger due to corrosion-related leaks that have caused in-flight shutdowns, particularly affecting Boeing 777 aircraft powered by these engines.
What Changed
This new airworthiness directive introduces mandatory inspections of the air/oil heat exchanger within 30 days prior to the first flight after May 2, 2022. Depending on inspection results, replacement of the air/oil heat exchanger is required. The directive also includes instructions for proper storage of inspected parts and is issued as an interim safety measure.
Why It Matters
This directive is critical for aviation professionals because corrosion-induced leaks in the air/oil heat exchanger can lead to low oil pressure, engine failure, and in-flight shutdowns, posing serious safety risks. Operators and maintenance teams must comply to prevent potential dual-engine shutdowns and loss of aircraft control, especially as affected Boeing 777 fleets return to service after extended storage.
What To Do
Operators of affected Pratt & Whitney engines must inspect the air/oil heat exchanger within 30 days before the first flight after May 2, 2022. If leaks or corrosion are found, the heat exchanger must be replaced following manufacturer instructions. Additionally, any inspected parts stored must follow the specified storage procedures to maintain airworthiness.
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