EASA AD CF-2021-29
Landing Gear — Nose Landing Gear — Nose Wheel Steering Selector Valve Slow to Deactivate
Summary
Canadian Airworthiness Directive CF-2021-29 addresses an issue with the nose wheel steering selector valve (SSV) on Bombardier Inc. model BD-100-1A10 aeroplanes, serial numbers 20003 through 20892. The directive mandates replacing the affected SSV part number 41130-107 with a redesigned part number 41130-111 to prevent slow deactivation under low temperature conditions. This AD aims to enhance safety by reducing the risk of runway excursions caused by delayed transition to free castor mode.
What Changed
CF-2021-29 introduces a requirement to replace the nose wheel steering selector valve P/N 41130-107 with the redesigned P/N 41130-111 within 36 months of the effective date. It also prohibits the installation of the older SSV P/N 41130-107 on the affected Bombardier BD-100-1A10 aircraft from the effective date onward. Additionally, it mandates testing of the new valve following installation according to Bombardier service bulletins.
Why It Matters
This directive is critical for operators and maintenance organizations to prevent potential runway excursions caused by slow deactivation of the nose wheel steering valve in cold conditions. Compliance ensures safer ground handling and steering control during taxi and takeoff. It also helps maintain regulatory compliance under Canadian Aviation Regulations and avoids operational disruptions or grounding due to non-compliance.
What To Do
Operators of Bombardier BD-100-1A10 aircraft with serial numbers 20003 through 20892 must replace the SSV P/N 41130-107 with the new P/N 41130-111 within 36 months from 2021-09-01. After replacement, they must perform the required testing as specified in the applicable Bombardier service bulletins SB 100-32-35 or SB 350-32-011 dated 30 March 2021. Installation of the old SSV P/N 41130-107 is prohibited from the effective date.
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