EASA AD CF-2016-11R3
Flight Controls - Corrosion of Bellcrank Pivot Bearings
Summary
Canadian Airworthiness Directive CF-2016-11R3 addresses corrosion issues in the bellcrank pivot bearings of Bell Textron Canada Limited model 429 helicopters. The directive mandates inspections and replacement of affected collective and cyclic bellcrank assemblies to prevent flight control restrictions caused by corrosion. It applies to all serial numbers of Bell 429 helicopters and requires compliance with Bell Alert Service Bulletin 429-15-21 Revision C or later.
What Changed
This revision CF-2016-11R3 supersedes the previous AD CF-2016-11R2 by mandating the installation of upgraded collective and cyclic bellcrank assemblies with corrosion resistant steel bearings as terminating action. It prohibits installation of affected bellcrank assemblies after 24 months from the effective date and limits corrective actions to helicopters that have not incorporated the upgrade in production. It also requires recurring functional checks every six months until the upgrade is installed.
Why It Matters
This directive is critical for operators and maintenance organizations to prevent flight control malfunctions caused by corroded bellcrank pivot bearings, which can lead to difficulty controlling the helicopter. Compliance ensures continued airworthiness and safety of Bell 429 helicopters by addressing a known corrosion risk that affects flight control reliability. It also clarifies inspection procedures and mandates use of improved parts to reduce maintenance burden and risk of undetected damage.
What To Do
Operators of Bell 429 helicopters must perform an initial functional check of the flight controls within 12 months from manufacture or within 30 days of the AD effective date if overdue. Recurring functional checks are required every six months until upgraded bellcrank assemblies are installed within 24 months of the AD effective date. Any detection of roughness or binding requires immediate replacement of both affected bellcrank assemblies with serviceable upgraded parts. Installation of affected bellcrank assemblies is prohibited after 24 months from the effective date.
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