AD 2022-06-20 Prompted By New Bellcrank Assemblies, Which Have Been Upgraded With Corrosion Resistant Steel Bearings

The FAA is superseding Airworthiness Directive (AD) 2020-20-06, which applied to certain Bell Helicopter Textron Canada Limited (now Bell Textron Canada Limited) Model 429 helicopters.

AD 2020-20-06 required repetitive inspections of certain cyclic and collective assembly bearings. This AD was prompted by new bellcrank assemblies, which have been upgraded with corrosion resistant steel bearings. This AD retains certain requirements of AD 2020-20-06, and depending on the inspection results, requires removing certain parts from service and installing the upgraded cyclic and collective bellcrank assemblies. This AD also requires installing the upgraded collective and cyclic bellcrank assemblies on certain helicopters if not already installed, and prohibits installing certain bellcrank assemblies. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective April 26, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2020-20-06, Amendment 39-21262 (85 FR 60356, September 25, 2020) (AD 2020-20-06). AD 2020-20-06 applied to Bell Helicopter Textron Canada Limited Model 429 helicopters with a bellcrank assembly part number (P/N) 429-001-523-101, 429-001-523-103, 429-001-532-101, or 429-001-532-103 installed. The NPRM published in the Federal Register on January 14, 2022 (87 FR 2362). In the NPRM, the FAA proposed to retain some of the requirements of AD 2020-20-06, and proposed to require, for certain serial-numbered helicopters, within 12 months after the helicopter was manufactured or 30 days, whichever occurs later, and thereafter at intervals not to exceed 6 months, disconnecting certain parts, stowing certain parts to prevent binding, and moving the cyclic stick and the collective stick to inspect for roughness in the flight control system and binding in the collective, lateral, and longitudinal arm assemblies. If any of these conditions exist, the NPRM proposed to require, before further flight, removing certain parts from service and installing upgraded bellcrank assemblies.

Additionally, the NPRM proposed to require, for certain serial-numbered helicopters that do not have the upgraded bellcrank assemblies installed, within 24 months, installing the upgraded bellcrank assemblies, which would provide a terminating action for the recurring inspections. Finally, the NPRM proposed to prohibit installing any affected bellcrank assembly on any helicopter.

The NPRM was prompted by Transport Canada AD CF-2016-11R3, dated August 30, 2021 (Transport Canada AD CF-2016-11R3), issued by Transport Canada, which is the aviation authority for Canada, to correct an unsafe condition for Bell Textron Canada Limited Model 429 helicopters, all serial numbers. Transport Canada advises of new collective and cyclic bellcrank assemblies which have been upgraded with corrosion resistant steel bearings. This condition, if not addressed, could result in restrictions in the collective, directional, or pitch control systems, and subsequent loss of helicopter control.

Accordingly, Transport Canada AD CF-2016-11R3 requires for certain serial-numbered helicopters, within 12 months from the helicopter manufacture date, or for helicopters that have exceeded the age threshold of 12 months from the helicopter manufacturer date, within 30 days, and thereafter at intervals not to exceed 6 months, performing a functional check of the flight controls to detect roughness in the pivot bearings and binding of the collective, lateral, or longitudinal arm end bearings of the bellcrank assemblies. If any roughness or binding is detected, Transport Canada AD CF-2016-11R3 requires replacement of each affected bellcrank assembly before further flight. Transport Canada AD CF-2016-11R3 also requires, within 24 months, installing the upgraded collective and cyclic bellcrank assemblies and considers this action a terminating action to the recurring inspections. Finally, Transport Canada AD CF-2016-11R3 prohibits an affected bellcrank assembly from being installed on any helicopter.

FMI: www.regulations.gov