AD/DHC-1/39 Flap Operating System Latch Plate (Cth)

AIRWORTHINESS DIRECTIVE

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 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 Flap Operating System Latch Plate 4/2009

Applicability:

English-built Model DHC-1 aircraft (all marks), fitted with flap operating system Latch Plate Part No. 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 9 April 2009, unless already accomplished.

This Airworthiness Directive becomes effective on 9 April 2009.

Background:

A report was received of the in-service failure of a flap operating system Latch Plate, supplied under Part No. 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.

David Punshon
Delegate of the Civil Aviation Safety Authority

5 February 2009