AD/DHC-1/40 Canopy Lock Modification (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-1/40 Canopy Lock - Modification 16/2011

Applicability:

All Canadian DHC-1B-2 Chipmunk aircraft serial numbers 139 to 195.

Requirement:

Modify the canopy lock mechanism in accordance with De Havilland Aircraft of Canada Limited Technical News Sheets C-38 and C-38 Amendment 2.

Note:  Transport Canada Airworthiness Directives CF-53-11 and CF-54-02 refer.

Compliance:

As stated in the requirement document unless previously incorporated.

This Airworthiness Directive becomes effective on 12 August 2011.

Background:

Difficulties have been reported in releasing the canopy due to the failure of the cable in the lock assembly.  DHC Canada then amended this modification using an improved lever assembly following reports of cracking.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

5 August 2011