AD/DHC-1/39 Amdt 1 Flap Operating System Latch Plate (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-1/39 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-1/39 Amdt 1 Flap Operating System Latch Plate 13/2011

Applicability:

English production (C1) all models and Portuguese (T Mk 20) production models, fitted with flap operating system latch plate Part Number C1-CF-1489; or where the part number of the installed Latch Plate is unknown.

Requirement:

Action in accordance with Chipmunk TNS CT (C1) No. 208.

Note:  UK CAA AD G-2009-0001 refers.

Compliance:

At the next scheduled maintenance inspection after the effective date of this AD, unless already accomplished.

This Amendment becomes effective on 23 June 2011.

Background:

A report was received of the in-service failure of a flap operating system Latch Plate, Part Number C1-CF-1489.  Investigation revealed that the part in question had not been manufactured in accordance with the applicable De Havilland drawing, and failed due to rapid wear.  Unless bogus latch plate(s) are detected and removed, failure could occur and result in uncommanded flap retraction.

This amendment is issued to include the Portuguese manufactured T Mk 20 model in the applicability of this Directive.

The original issue of this AD became effective on 9 April 2009.

Glen Steemson
Delegate of the Civil Aviation Safety Authority

17 June 2011