AD/DHC-1/36 Amdt 2 Flap Operating Cables (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/DHC-1/36 Amdt 1 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.

De Havilland DHC-1 (Chipmunk) Series Aeroplanes

AD/DHC-1/36 Amdt 2 Flap Operating Cables 12/2011

Applicability:

English production (C1) all models and Portuguese (T Mk 20) production models.

Requirement:

Action in accordance with British Aerospace TNS CT(C1) No.184 Issue 4.

Note:  UK CAA AD 001-03-95 refers.

Compliance:

At intervals not to exceed 150 flight hours or at the annual inspection, whichever occurs first.

This Amendment becomes effective on 21 June 2011.

Background:

Cases have been reported of failure of the Flap operating cable which in one case led to a flap asymmetry situation during the final phase of landing.  Investigation has shown the failures were due to either incorrect rigging of the control cables or inadequate maintenance of the control pulleys.

Amendment 1 was issued in response to a revision of the Requirement document, which introduced a repetitive inspection of the latch plate and flap lever quadrant for wear.

This inspection was originally introduced in 1995, and up until now, Australia has had no Portuguese manufactured Chipmunks on the register, hence the CASA AD has only been effective for English production Chipmunks.

This amendment is to include the Portuguese manufactured Chipmunk in the applicability for this AD, as a recent review of documents, shows that this inspection is also applicable to the Portuguese model (T Mk 20).

There are no technical changes to the requirements or compliance of this AD.

Glen Steemson
Delegate of the Civil Aviation Safety Authority

16 June 2011