EASA AD CF-2021-12
Fire Protection System — Main Landing Gear Primary Zone Advanced Pneumatic Detector Chafing Damage
Summary
Canadian Airworthiness Directive CF-2021-12 addresses fire protection system concerns related to the main landing gear primary zone advanced pneumatic detector chafing damage on De Havilland DHC-8-401 and -402 aircraft, serial numbers 4001 and 4003 through 4614. The directive mandates inspections and repairs to prevent hydraulic leaks and fire detection failures caused by insufficient clearance and chafing between hydraulic tubes and APD sensing lines. This AD ensures continued airworthiness and safety of the affected aircraft models.
What Changed
CF-2021-12 introduces a new requirement for detailed visual inspections and rectifications of the left and right main landing gear primary zone APD sensing lines, hydraulic tube assemblies, and surrounding structures. It mandates compliance within 48 months or 8000 flight hours from the effective date. The directive also recognizes compliance with De Havilland Service Bulletin 84-26-20, Revision NC or later revisions as meeting the AD requirements.
Why It Matters
This directive is critical for aviation professionals as it prevents potential hydraulic fluid leaks and loss of fire detection capability in the main landing gear area, which could compromise flight safety. Operators and maintenance organizations must ensure timely inspections and repairs to avoid operational disruptions and regulatory non-compliance. Compliance helps maintain system integrity and reduces the risk of in-flight emergencies related to fire protection systems.
What To Do
Operators of affected De Havilland DHC-8-401 and -402 aircraft must perform detailed visual inspections and necessary repairs on the main landing gear APD sensing lines and hydraulic tubes within 48 months or 8000 flight hours from April 14, 2021. They should follow the procedures outlined in De Havilland Service Bulletin 84-26-20, Revision A or later approved revisions. Documentation of compliance and any corrective actions must be maintained as per regulatory requirements.
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