AD/Bell 430/1 Amdt 4 Tail Rotor Blade (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BELL 430/1 Amdt 3 and issues the following 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 430/1 Amdt 4 Tail Rotor Blade 7/2008 DM

Applicability:

Model 430 helicopters.

Requirement:

1.    Inspect the tail rotor blades in accordance with Part I of Bell Helicopter Textron Canada Alert Service Bulletin (ASB) 430-04-31 Revision B, or later Transport Canada approved revision.

2.    Inspect the tail rotor blades in accordance with Part II of ASB 430-04-31 Revision B, or later Transport Canada approved revision.

3.    Rework the affected tail rotor blades in accordance with Part III of ASB
430-04-31 Revision B, or later Transport Canada approved revision.

Note 1:  Reworking the tail rotor blades in accordance with Requirement 3 eliminates the repetitive inspection requirements of this Directive.

Note 2:  Transport Canada AD CF-2004-21 R3 refers. 

Compliance:

1.    Unless the initial inspection is already accomplished, within 3 flight hours after
1 June 2008, and thereafter at intervals not to exceed 3 flight hours.

2.    Unless the initial inspection is already accomplished, within 50 flight hours after 1 June 2008, and thereafter at intervals not to exceed 50 flight hours.

3.    Before 31 December 2008, unless already accomplished.

This Directive shall be entered on the Maintenance Release as maintenance required.  The Requirement 1 inspection may be performed and certified by the Pilot in Command who has been trained to do the inspection by an appropriately qualified person.  In this case, a copy of the Requirement document and this Directive is to be carried on the aircraft.

This Amendment becomes effective on 1 June 2008.

Background:

Reports were received of three occurrences of cracked tail rotor blades; discovered during scheduled inspection.  Two cracks initiated from the outboard bearing bore underneath the flanged sleeves.  The third crack initiated from the inboard bearing bore.  Corrosion and machining burrs are suspected as the crack initiators.

Amendment 1 clarified applicability and allowed the pilot to accomplish Requirement 1 inspections.

Amendment 2 expanded applicability but with no change to technical content.

Amendment 3 introduced terminating action for the repetitive inspection requirements.

Amendment 4 is issued in response to a revision of the related Transport Canada AD, which extends terminating action until 31 December 2008.

David Villiers
Delegate of the Civil Aviation Safety Authority

19 May 2008