AD/CL-600/68 Aileron Power Control Unit Links (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 (Canadair) CL-600 (Challenger) Series Aeroplanes

AD/CL-600/68 Aileron Power Control Unit Links 10/2005

Applicability:

Bombardier CL-600-2C10, serial numbers 10003 and subsequent.

Bombardier CL-600-2D15 and CL-600-2D24, serial numbers 15001 and subsequent.

Requirement:

1.    Accomplish the following in accordance with Bombardier ASB A670BA-27-023, Revision A, dated 18 May 2005, or later Transport Canada approved revisions:

(a)   Conduct a detailed visual inspection of the four aileron PCU output links for fractures/cracks and replace any fractured/cracked links prior to further flight;

(b)   As part of the replacement of any fractured/cracked link, perform the following checks:

(i)    Measure the torque value of the forward and aft attachment bolts for both the damaged PCU output link and the adjacent PCU output link;

(ii)   For any damaged link, check for and if required, measure, any mismatch between PCU output link and the aileron lugs;

(iii)  For any damaged link, perform an eddy current inspection of the aileron lugs and the flange bushings of the aileron lug; and if crack found or suspected, contact the Technical Help Desk, Bombardier Aerospace for instructions; and

(iv)  Record the information requested in Appendix A of the above mentioned Bombardier ASB.

Note 1:  Inspections and checks carried out in accordance with Bombardier ASB A670BA-27-023, dated 3 May 2005, also meet the requirements of Requirement 1 of this directive.

2.    Forward the information requested in Appendix A of the above mention ASB, to Bombardier Aerospace at the address provided in the ASB.

3.    Repeat the visual inspection and if required, the special check for fractured/cracked links, detailed above in Requirements 1(a) and 1(b) of this directive.

Note 2:  Transport Canada AD CF-2005-23 refers.

Compliance:

1.    Comply with the following schedule:

(a)   Aircraft that have accumulated 2000 hours time in service (TIS) or more upon the effective date of this directive; prior to accumulating 550 hours TIS from the effective date of this directive; and

(b)   Aircraft with less than 2000 hours TIS upon the effective date of this directive; prior to reaching 2000 hours TIS or prior to accumulating 550 hours TIS from the effective date of this directive, which ever is reached later.

2.    Within 14 days of completing the inspection.

3.    At intervals not to exceed 1000 flight hours.

This Airworthiness Directive becomes effective on 29 September 2005.

Background:

Transport Canada has received reports of aileron power control unit (PCU) link fractures on in-service CL-600-2B19 aircraft.  The same links are also used on the CL-600-2C10, CL-600-2D15 and CL-600-2D24 aircraft.  Failure of one PCU link may result in a dormant failure; failure of both PCU links to an aileron could result in reduced lateral control of the aircraft.

James Coyne
Delegate of the Civil Aviation Safety Authority

18 August 2005