EASA AD CF-2025-66
Engine — Compressor Turbine (CT) Disk Assembly — Unsubstantiated CT Disk Part Number (P/N) in Engine Technical Publications
Summary
Canadian Airworthiness Directive CF-2025-66 addresses an error in the technical publications for Pratt & Whitney Canada PT6T-3 engines involving an unsubstantiated compressor turbine disk part number (P/N 3024211). This directive applies to all serial numbers of the PT6T-3 engine model and mandates verification and correction of the installed CT disk part number to ensure compliance with airworthiness limitations. The AD aims to prevent potential compressor turbine disk failure and subsequent engine or aircraft damage.
What Changed
CF-2025-66 introduces a requirement to confirm the CT disk part number installed on PT6T-3 engines and remove P/N 3024211 if found. It also prohibits the installation of this part number going forward. The directive incorporates updated service bulletins and illustrated parts catalogue revisions to correct the previously published erroneous data.
Why It Matters
This directive is critical for operators and maintenance organizations to avoid the risk of compressor turbine disk failure due to the use of a part number without established life limits. Ensuring compliance protects engine integrity and aircraft safety while maintaining regulatory adherence. It also clarifies maintenance records and parts installation to prevent inadvertent use of unapproved components.
What To Do
Operators must verify the CT disk part number on all PT6T-3 engines within 100 flight hours or 6 months from December 19, 2025, whichever occurs first. If P/N 3024211 is installed, it must be removed and replaced following the instructions in P&WC Service Bulletin PT6T-72-5586 Revision 1 before further flight. Installation of P/N 3024211 is prohibited from the effective date of the AD.