AD/SD3-60/68 Amdt 1 Elevator Trim Tab Balance Weight Brackets (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/SD3-60/68 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.

Short SD3-60 Series Aeroplanes

AD/SD3-60/68 Amdt 1 Elevator Trim Tab Balance Weight Brackets 8/2005

Applicability:

All Model SD3-60 aircraft.

Requirement:

1.    For aircraft fitted with new part number SD3-07-6011 elevator trim tab balance weight brackets originally installed in accordance with Part B of Shorts Service Bulletin (SB) SD360-55-20, initial issue; and subsequently inspected but not replaced in accordance with Shorts Alert Service Bulletin (ASB) SD360-55-A21, inspect the elevator trim tab balance weight brackets in accordance with Part A of ASB SD360-55-A21.  Replace the elevator trim tab balance weight brackets with fully conforming brackets in accordance with Part B of ASB SD360-55-A21, or later EASA approved revision.

2.    For aircraft fitted with part number SD3-31-6213xB elevator trim tab balance weight brackets previously inspected in accordance with SB SD360-55-20, initial issue and refitted as-is or following approved repair in accordance with Part B of SB SD360-55-20, inspect the elevator trim tab balance weight brackets in accordance with SB SD360-55-20 Revision 1.  Replace the elevator trim tab balance weight brackets with fully conforming brackets in accordance with Part B of SB SD360-55-20 Revision 1, or later EASA approved revision.

Cracked brackets must be replaced with reworked brackets before further flight with new fully conforming brackets in accordance with Part B of ASB SD360-55-A21 or Part B of SB SD360-55-20 Revision 1, later EASA approved revision.

For aircraft with elevator trim tab balance weight brackets that have been replaced with new fully conforming brackets in accordance with Part B of ASB SD360-55-A21 or SB SD360-55-20 Revision 1, no further action is required by this Directive.

Note:  UK CAA AD G-2005-0013 refers.

Compliance:

1.    For the inspection:  Within 250 flight hours since the last inspection, and thereafter at intervals not to exceed 250 flight hours.

For the replacement:  Before the accumulation of 1,750 flight hours since new.

2.    For the inspection:  Within 4,800 flight hours since the last inspection, and thereafter at intervals not to exceed 4,800 flight hours.

For the replacement:  Before the accumulation of 28,800 flight hours since new.

This Amendment becomes effective on 4 August 2005.

Background:

During a routine structural inspection, an operator found that the elevator tab balance weight brackets on both trim tabs were cracked.  Examination of the cracked brackets by the aircraft manufacturer determined that they were not manufactured in conformity to the approved design standard.  The non-conformity has the potential to greatly reduce the fatigue life of the brackets, causing premature crack initiation and failure.

Amendment 1 is issued in response to a new UK CAA AD, which cancels previously issued ADs 009-06-2003 (AD/SD3-60/66) and G-2004-0032.  This action is in response to an investigation by the Type Certificate Holder which revealed the new brackets were not manufactured in conformity with the applicable design data.

David Villiers
Delegate of the Civil Aviation Safety Authority

21 June 2005