EASA AD CF-2018-11
Landing Gear — Uncommanded Nose Wheel Steering Due to Failure of the Steering Selector Valve
Summary
Canadian Airworthiness Directive CF-2018-11 addresses uncommanded nose wheel steering issues on Bombardier Inc. model BD-100-1A10 aeroplanes, serial numbers 20002 to 20744. The directive mandates modifications to the hydraulic system to prevent steering selector valve failures caused by hydraulic contamination. This safety measure aims to reduce the risk of runway excursions due to nose wheel steering malfunctions.
What Changed
This new Airworthiness Directive introduces a requirement to install a hydraulic fluid filter in the left hand hydraulic system line supplying pressure to the nose wheel steering system. It also mandates retroactive torque checks on specific tube assembly fittings for aircraft that have previously incorporated earlier revisions of the related service bulletins. The directive accepts later approved revisions of the service bulletins for compliance.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk involving uncommanded nose wheel steering that could lead to runway excursions. Operators and maintenance teams must ensure compliance to maintain aircraft airworthiness and operational safety. The directive also provides clear instructions on corrective actions and acceptable compliance methods, facilitating effective maintenance planning and regulatory adherence.
What To Do
Operators of affected Bombardier BD-100-1A10 aircraft must modify the left hand hydraulic system by installing a hydraulic fluid filter within 2000 flight cycles or 60 months from 2018-04-19, whichever occurs first. For aircraft that incorporated earlier revisions of the service bulletins, torque the fittings on the specified tube assembly within 50 flight hours from the effective date. Use the latest approved revisions of Bombardier Service Bulletin 100-32-31 or 350-32-007 for compliance.
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