AD 2021-20-11 Prompted By Reports Of Incorrectly Staked Spherical Bearings In The Directional Control Bellcrank Assembly

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (type certificate previously held by Bell Helicopter Textron Canada Limited) Model 429 helicopters.

This AD was prompted by reports of incorrectly staked spherical bearings in the directional control bellcrank assembly. This AD requires a one-time inspection of the lower surface of the spherical bearing in the directional control bellcrank assembly to determine if it is properly staked and, depending on the findings, applicable corrective actions. For certain helicopters, this AD also requires repetitive inspections and, depending on the findings, applicable corrective actions. This AD also provides a terminating action for the repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 22, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Bell Textron Canada Limited (type certificate previously held by Bell Helicopter Textron Canada Limited) Model 429 helicopters. The NPRM published in the Federal Register on July 23, 2021 (86 FR 38946). In the NPRM, the FAA proposed to require a onetime inspection of the lower surface of the spherical bearing in the directional control bellcrank assembly to determine if it is properly staked and, depending on the findings, applicable corrective actions. In the NPRM, the FAA also proposed to require, for certain helicopters, repetitive inspections and, depending on the findings, applicable corrective actions. The NPRM was prompted by Transport Canada AD CF-2020-11, dated April 16, 2020 (Transport Canada AD CF-2020-11), issued by Transport Canada, which is the aviation authority for Canada, to correct an unsafe condition for Bell Textron Canada Limited (Bell) Model 429 helicopters, serial numbers 57001 through 57210, 57212 through 57344, 57346 through 57371, 57374 through 57377, and 57380.

Transport Canada advises that there are reports of incorrectly staked spherical bearings in the directional control bellcrank assembly. This condition, if not addressed, could result in wear or elongation of the bore in the bellcrank, which could result in reduced helicopter directional control.

Accordingly, Transport Canada AD CF-2020-11 requires a one-time inspection to determine if a spherical bearing is properly staked in the directional control bellcrank assembly, and, depending on the findings, replacement of the spherical bearing with a new spherical bearing, repair of an affected bellcrank assembly and repetitive inspections of that repaired bellcrank assembly, or replacement of the affected bellcrank assembly with a serviceable part. Transport Canada AD CF-2020-11 also provides terminating actions for the requirements of that AD.

FMI: www.regulations.gov