Auxiliary Power Unit (APU) — APU Muffler Drainage Blockage Causing Fuel Leakage Accumulation
- Published
- Effective
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of Bombardier CL-600-2A12 and CL-600-2B16 aircraft must perform the required functional tests of the APU exhaust muffler drainage system within the specified thresholds and intervals outlined in the updated maintenance manuals. They should follow the temporary revisions published by Bombardier and approved by Transport Canada. Compliance with this directive is mandatory from February 3, 2025, and must be maintained through ongoing inspections as specified.
Summary
The Canadian Airworthiness Directive CF-2025-06 addresses an issue with the Auxiliary Power Unit (APU) muffler drainage blockage causing fuel leakage accumulation on Bombardier Inc. CL-600-2A12 and CL-600-2B16 aircraft models. This directive mandates inspections and functional tests of the APU exhaust muffler drainage system to prevent fuel accumulation and potential fire hazards. It applies to all serial numbers of the affected Bombardier Challenger aircraft variants.
What changed
CF-2025-06 introduces a new airworthiness directive requiring operators to perform functional tests on the APU exhaust muffler drainage circuit to detect and prevent blockages that could lead to fuel leakage and fire. It also references specific temporary revisions to the Bombardier maintenance manuals that detail the inspection procedures and compliance intervals.
Why it matters
This directive is critical for aviation professionals as it addresses a safety risk involving potential uncontrolled fires in the APU compartment due to fuel accumulation from drainage blockages. Compliance ensures the continued airworthiness of affected Bombardier Challenger aircraft and helps prevent in-flight or post-landing fire incidents. Maintenance and compliance teams must integrate these inspections into their routine procedures to meet regulatory requirements and maintain operational safety.
More for Bombardier CL-600 (Challenger)
All 47- EASA AD CF-2026-41Time Limits/Maintenance Checks – Airworthiness Limitations – AmendmentAug 24, 2026
- EASA AD CF-2025-51R1Flight Controls — Uncommanded and Unarrested Flap MovementDec 2, 2025
- EASA AD CF-2025-36Fuselage, Stabilizers, Wings, Exhaust SystemJul 9, 2025
- EASA AD CF-2025-05Landing Gear — Uncommanded SteeringJan 27, 2025
- EASA AD CF-2024-47
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