Ad/DHC-8/143 - Nose Landing Gear Electrical Harness (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.

Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes

AD/DHC-8/143 Nose Landing Gear Electrical Harness 10/2008

Applicability:

Model DHC-8-400, DHC-8-401 and DHC-8-402 aircraft, Serial Numbers 4003, 4004, 4006 and 4008 through 4184.

Requirement:

Replace the weight-on-wheels and steering harnesses by incorporating Modsum
4-126401.  Bombardier Service Bulletin (SB) 84-32-51, Revision B, dated 17 December 2007, or later revisions approved by Chief, Continuing Airworthiness, Transport Canada, provides approved instructions for incorporating Modsum
4-126401.

Note 1:  Incorporation of Modsum 4-126401 in accordance with the original issue of SB 84 32 51, dated 16 August 2007 or with Revision A, dated 22 August 2007, before the effective date of this Directive is acceptable for compliance with this Directive.

Note 2:  Transport Canada AD CF-2008-22 dated 24 June 2008 refers.

Compliance:

Within 2,500 hours time in service after the effective date of this Directive.

This Airworthiness Directive becomes effective on 25 September 2008.

Background:

There have been several cases reported where the landing gear did not retract after take off.  Subsequent investigation revealed this was caused by fatigue failure of the nose landing gear electrical harness.  In conjunction with one engine being inoperable, this could, in certain operating conditions, affect continued safe flight and landing

This Directive mandates incorporation of new weight-on-wheels and steering harnesses that have a new conduit construction.

James Coyne
Delegate of the Civil Aviation Safety Authority

6 August 2008