AD/Bell 430/9 Yaw Synchro Resolver Shaft Control Arm Screw (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Bell Helicopter Textron Canada (BHTC) 430 Series Helicopters

AD/BELL 430/9 Yaw Synchro Resolver Shaft
Control Arm Screw 12/2006

Applicability:

Model 430 helicopters, serial numbers 49001 through 49018, 49020 through 49043, and 49045 through 49051.

Requirement:

Install screws part number 1352-04-8P and guard brackets in accordance with the Accomplishment Instructions of BHTC Alert Service Bulletin 430-99-11, or later Transport Canada approved revision.

Note:  Transport Canada AD CF-99-26 refers.

Compliance:

Unless already accomplished, before 23 December 2006.

This Airworthiness Directive becomes effective on 23 November 2006.

Background:

A yaw control channel malfunctioned during a check for freedom of controls following maintenance.  The screw that clamps the control arm to the yaw synchro resolver shaft was loose, allowing the control arm to separate from the shaft and to jam against an airframe stringer.

David Villiers
Delegate of the Civil Aviation Safety Authority

12 October 2006