AD/DHC-1/31 Amdt 3 Fin Rear Spar (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-1/31 Amdt 2 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-1/31 Amdt 3 Fin Rear Spar 13/2011

Applicability:

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

Requirement:

Inspect the fin structure for cracks and corrosion in accordance with paragraphs 2.4, 3.6 and 4 of British Aerospace Technical News Sheet (TNS) CT (C1) No. 156 Issue 5 or later revision published by British Aerospace Aerostructures Limited.

Conduct dye penetrant inspections in accordance with CAO 108.10.

Modification H283 performed in accordance with Note 1 of TNS No. 156 Issue 5 terminates the requirement for the inspections described in paragraph 3.

Compliance:

Inspect at intervals not to exceed 3 years or 600 hours, whichever occurs first.

Compliance with Amendment 1 constitutes compliance with this Amendment.

This Amendment becomes effective on 23 June 2011.

Background:

British Aerospace has reported that cracks have been found in the fin rear spar at a number of critical locations, and that corrosion has been found in the internal fin structure.

This amendment includes the Portuguese manufactured (T Mk 20) in the applicability of this AD.  A recent review indicates that the inspection required by this AD is applicable to this model.

Amendment history:

Amendment 1 incorporated Issue 4 of TNS No. 156, which revised paragraph 5 inspection interval from 6 years or 600 hours, to 3 years or 600 hours.

Amendment 2, effective 30 July 2010, incorporated Issue 5 or later revision of TNS No. 156.

Glen Steemson
Delegate of the Civil Aviation Safety Authority

17 June 2011