Flight Controls — Trailing Edge Flap Cable Tension - Rigging
- Published
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators and maintenance personnel should use the latest revision of the applicable Textron Aviation service manuals when performing flap cable rigging to ensure correct tension settings for extension and retraction cables. No compliance deadline is specified, but adherence to updated maintenance procedures is strongly recommended to mitigate flap cable failure risks.
Summary
The FAA Special Airworthiness Information Bulletin SAIB: AIR-21-20 addresses flap cable tension and rigging concerns for Textron Aviation Inc. (formerly Cessna Aircraft Company) Model 310 series, 320 series, 335, 340 series, 401 series, 402 series, 411 series, 414 series, 421 series, and 425 airplanes. It highlights the importance of correctly setting trailing edge flap cable tensions during maintenance to prevent cable failure. This bulletin is informational and does not mandate regulatory action.
What changed
SAIB AIR-21-20 introduces an emphasis on the correct tensioning of flap extend and retract cables, noting that the flap extend cable requires significantly lower tension than the retract cable. It also informs operators of revised Textron Aviation manuals that clarify these differences in cable rigging tensions. The bulletin does not impose new regulatory requirements but provides updated guidance to prevent flap cable failures.
Why it matters
Proper flap cable tensioning is critical to maintaining flight control integrity and preventing in-flight flap extend cable failures, which can cause sudden roll and yaw during approach. Aviation professionals, including maintenance technicians and inspectors, must understand the different tension requirements to avoid cable failure or interference with airplane structure. This guidance helps ensure safe operation and reduces the risk of flap system malfunctions.
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