EASA AD CF-2009-29R4
SUPERSEDED BY TCCA AD CF-2023-22
Summary
The Canadian Airworthiness Directive CF-2009-29R4 addresses safety concerns on De Havilland Aircraft of Canada Limited DHC-8-401 and -402 aeroplanes, specifically related to the nose landing gear pivot pin retention bolt. This directive mandates modifications and maintenance procedures to prevent loss or damage of the retention bolt, which could lead to loss of nose wheel steering and directional control during take-off or landing. The directive applies to aircraft serial numbers 4001, 4003, and subsequent.
What Changed
AD CF-2009-29R4 introduces an initial compliance time for lubrication of the trailing arm, changes the lubrication interval measurement from hours air time to flight cycles, and removes the previous requirement to lubricate the retention bolt itself. It cancels all prior Transport Canada approvals for alternative means of compliance related to earlier revisions of this AD and establishes new maintenance tasks and life limits for the affected bolts.
Why It Matters
This directive is critical for aviation professionals to ensure the structural integrity and safe operation of the nose landing gear on affected DHC-8 Series 400 aircraft. Compliance prevents potential failures that could cause loss of directional control or tire rupture during critical phases of flight, thereby enhancing flight safety. Maintenance and compliance teams must update maintenance schedules and procedures to align with the new requirements to avoid regulatory non-compliance and operational risks.
What To Do
Operators must perform the required modifications to the nose landing gear shock strut assembly within 1600 flight cycles or 9 months from the previous AD's effective date, amend maintenance schedules within 30 days of modification completion, and implement repetitive lubrication of the trailing arm every 400 flight cycles. Additionally, life limits for the retention bolts must be incorporated, and bolts replaced as specified, with some replacements required within 3 months or 800 flight cycles depending on prior compliance.
AI-generated summary from official EASA source document. Always verify against the original.