AD/Bell 427/7 Tail Rotor Blades (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 427 Series Helicopters

AD/BELL 427/7 Tail Rotor Blades 13/2007

Applicability:

All Model 427 series helicopters.

Requirement:

Verify if the affected blades are installed on the helicopter in accordance with BHTC Alert Service Bulletin (ASB) 427-07-18, or later Transport Canada approved revision.

Remove any affected blades before further flight and replace with serviceable parts.

Note:  Transport Canada Emergency AD CF-2007-21 refers.

Compliance:

Before further flight after 20 December 2007, unless already accomplished.

This Airworthiness Directive becomes effective on 20 December 2007.

Background:

Transport Canada received three reports of balance weights departing from tail rotor blades during flight.  The cause has been narrowed down to missing weight screws.  This failure can occur at any time.

David Villiers
Delegate of the Civil Aviation Safety Authority

7 November 2007