AD/DHC-2/24 Amdt 4 Wing Strut Assembly Lower Attachment Fittings (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-2/24 Amdt 3 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.

DHC-2 (Beaver) Series Aeroplanes

AD/DHC-2/24 Amdt 4 Wing Strut Assembly Lower
Attachment Fittings 3/2007

Applicability:

All Models DHC-2 aircraft fitted with wing lift strut part numbers C2W1103, C2W1103A, C2W1104, or C2W1104A.

Requirement:

Part A - Inspection using fluorescent penetrant method.

Action in accordance with the Accomplishment Instructions of Viking Air Ltd (formerly Bombardier/de Havilland Canada) Service Bulletin No. 2/41 Revision C, dated 23 June 2006, or a later Transport Canada approved revision.  The fluorescent penetrant inspection of the lower clevis fitting shall be carried out by a person holding a valid appropriate Non-Destructive Testing Authority.

Part B - Inspection using Eddy Current method.

Action in accordance with the Accomplishment Instructions of Viking Air Ltd Service Bulletin No. 2/55, dated 23 June 2006, or a later Transport Canada approved revision.

Note:  Transport Canada AD CF-1985-08R4 refers.

Compliance:

Part A - Inspection using fluorescent penetrant method.

For aircraft operating in a salt water environment:

I.     For aircraft which have complied with Amendment 3 of this Directive, within one calendar year since the previous inspection, and thereafter at intervals not to exceed one calendar year; and

II.    For aircraft which have not complied with Amendment 3 of this Directive, within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed one calendar year.

For all other aircraft:

I.     For aircraft which have complied with Amendment 3 of this Directive, within two calendar years since the previous inspection, and thereafter at intervals not to exceed two calendar years; and

II.    For aircraft which have not complied with Amendment 3 of this Directive, within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed two calendar years.

Part B - Inspection using Eddy Current method.

For aircraft operating in a salt water environment:

I.     For aircraft which have complied with Amendment 3 of this Directive, within one calendar year since the previous inspection, thereafter at intervals not to exceed two calendar years; and

II.    For aircraft which have not complied with Amendment 3 of this Directive, within 100 flight hours or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed two calendar years.

For all other aircraft:

I.     For aircraft which have complied with Amendment 3 of this Directive, within two calendar years since the previous inspection, and thereafter at intervals not to exceed five calendar years; and

II.    For aircraft which have not complied with Amendment 3 of this Directive, within 100 flight hours or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed five calendar years.

If cracks are detected during any Part A or Part B inspection required by this Directive, before further flight, remove the affected strut from service.

This Amendment becomes effective on 15 March 2007.

Background:

A report was received of stress corrosion cracking occurring in the wing lift strut lower clevis fitting.  This Directive requires certain actions in order to preclude failure of the wing lift strut.

Amendment 1 expanded the part number applicability and removed the serial number range and date of manufacture provisions.

Amendment 2 replaced the dye penetrant inspection with the fluorescent penetrant inspection.

Amendment 3 allowed a longer inspection interval for aircraft which are not operated in a salt water environment.

Amendment 4 is issued in response to a revision of the related Transport Canada AD, which allows operators the option of continuing with the current inspection intervals or incorporating the improved alternate inspection method, to permit an increase in inspection intervals.

David Villiers
Delegate of the Civil Aviation Safety Authority

2 February 2007