EASA AD CF-2018-12
Engine — Material Anomaly for Certain High Pressure (HP) Centrifugal Impellers
Summary
The Canadian Airworthiness Directive CF-2018-12 addresses a material anomaly in certain Pratt & Whitney Canada PW150A engine high pressure (HP) centrifugal impellers. This directive applies to impellers with specific serial numbers listed in P&WC Service Bulletin 35331 Revision 1. It aims to prevent severe engine and aircraft damage caused by potential impeller failure due to a microstructure anomaly.
What Changed
CF-2018-12 introduces mandatory restrictions on the installation of affected HP centrifugal impellers and requires their removal and replacement before reaching 8000 flight cycles. It enforces compliance with P&WC Service Bulletin 35331 Revision 1 or later approved revisions, differing from the original service bulletin's recommended compliance times.
Why It Matters
This directive is critical for aviation professionals to ensure engine safety and airworthiness by addressing a manufacturing defect that reduces the low cycle fatigue life of specific PW150A engine impellers. Operators and maintenance organizations must comply to avoid potential engine failures and associated aircraft damage, maintaining regulatory compliance under Canadian Aviation Regulations.
What To Do
Operators must not install uninstalled HP centrifugal impellers with affected serial numbers after the effective date of May 11, 2018. Affected impellers installed on engines must be removed and replaced before accumulating 8000 flight cycles, following the instructions in P&WC Service Bulletin 35331 Revision 1 or later approved revisions. Compliance must be ensured promptly to maintain airworthiness.
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