AD/UH-1/20 Tail Boom and Fin - Fretting and Cracking (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 issues the following Airworthiness Directive (AD) under subregulation 39.001 (1) of CASR. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct an 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 UH-1 (All Variants) Series Helicopters

AD/UH-1/20 Tail Boom and Fin - Fretting and Cracking 20/2019

Applicability:

All models of Bell Helicopter Textron Inc UH-1 Series Helicopters.

Requirement:

Action in accordance with the technical requirements of Federal Aviation Administration of the United States of America (FAA) Airworthiness Directive (AD) 83-03-03 Amdt 39-4556 (FAA AD), as in force at the date of this AD.

Note 1:  The FAA AD paragraph b. references FAA Advisory Circular (AC) 43-13-1A paragraph 298, and FAA AC 43-3 Chapter 2 which have been superseded by FAA AC 43-13-1B. FAA AC 43-13-1B Chapter 5 Section 2 can be used in lieu of both FAA AC 43-3 (Chapter 2) and paragraph 298 of FAA AC 43-13-1A.

Note 2:  A different non-destructive inspection method, other than the radiographic inspection method, to that detailed in the FAA AD can be used if approved by CASA in writing as an alternative method of compliance.

Compliance:

As specified in the Requirement document, but with a revised initial inspection date of within 14 days after the commencement date of this AD, unless previously accomplished.

This AD commences on 2 October 2019.

Background:

FAA AD 83-03-03 Amdt 39-4556 effective 14 March 1983 was issued to detect cracks and prevent possible failure of the tail boom and fin. The FAA had determined that tail boom skin cracks occurred in a model UH-1B which crashed. A metallurgical examination revealed cracks to be due to structural fatigue.

Since this condition is likely to exist or develop on other helicopters of the same design, the FAA AD was issued. The AD requires visual and radiographic inspections for fretting and cracking, and repair or replacement, as necessary, of the tail boom skin and the fin spar cap on Bell Helicopter Textron Inc Model UH-1 series helicopters.

CASA’s predecessor conducted a review of FAA AD 83-03-03 Amdt 39-4556 on 9 March 1983. At the time of the review no Bell Helicopter Textron Inc UH-1 series helicopters were on the Australian civil aircraft register.

It has since come to CASA’s attention that Bell Helicopter Textron Inc UH-1 series helicopters have now been placed on the Australian civil aircraft register and will require inspections to be accomplished in accordance with FAA AD 83-03-03 Amdt 39-4556.

Pieter van Dijk
Delegate of the Civil Aviation Safety Authority

25 September 2019