AD/CL-600/116 Air Driven Generator Strut (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-600/116 Air Driven Generator Strut 9/2009

Applicability:

Bombardier Inc. Models:

CL-600-2B19, Serial Numbers (S/N) 7305 through 8051.

CL-600-2C10, S/Ns 10003 through 10260.

CL-600-2D15 and CL-600-2D24, S/Ns 15001 through 15106.

Requirement:

1.    Identification Check:

Check the Part Number (P/N) of the installed Air Driven Generator (ADG):

a.     If the ADG has Hamilton Sundstrand P/N 1711405, the strut wall thickness is within specification.  No further action is required and compliance with this AD is complete.

b.    If the ADG has a Hamilton Sundstrand P/N in the 761339 series, check the ADG S/N and proceed as follows:

i.     If the S/N of the ADG is 2000 or higher, the strut wall thickness is within specification.  No further action is required and compliance with this AD is complete.

ii.     If the S/N of the ADG is in the range 0101 through 1999 and symbol
24-3 is marked in the S/N block of the identification plate, the strut wall thickness is within specification.  No further action is required and compliance with this AD is complete.

iii.    If the S/N of the ADG is in the range 0101 through 1999 and symbol
24-3 is not marked in the S/N block of the identification plate, check the S/N of the strut and generator housing assembly (for location, see
Figure 1, Sheet 1 of Hamilton Sundstrand Service Bulletin (SB) ERPS10AG-24-3) and proceed as follows:

A.   If the S/N of the strut and generator housing assembly is in the range 0001 through 2503, a fluorescent penetrant inspection is required.  Proceed to Requirement 2 of this AD.

B.    If the S/N of the strut and generator housing assembly is 2504 or higher, the strut wall thickness is within specification.  No further action is required and compliance with this AD is complete.

iv.    If the S/N of the strut and generator housing assembly is not checked, fluorescent penetrant inspection is required.  Proceed to Requirement 2 of this AD.

Note 1:  Requirement 1 may be conducted visually, which requires the ADG to be lowered, or by checking the maintenance records.

2.    Fluorescent Penetrant Inspection:

a.     Applicable to CL-600-2B19 Aircraft, S/Ns 7305 through 8051:

Inspect the ADG strut, and replace the ADG as necessary, in accordance with the Accomplishment Instructions in Bombardier Alert Service Bulletin (ASB) A601R-24-120, Revision C, dated 20 April 2009, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Prior accomplishment of the fluorescent penetrant inspection, conducted in accordance with either the above referenced SB or one of the SBs listed in Table 1 of this AD, also meets the intent of Requirement 2 of this AD.

Table 1

Bombardier Alert SB A601R-24-120	Original Issue	Dated 20 April 2005
Bombardier Alert SB A601R-24-120	Revision A	Dated 1 December 2005
Bombardier Alert SB A601R-24-120	Revision B	Dated 7 December 2006
Hamilton Sundstrand SB ERPS10AG-24-3	Original Issue	Dated 14 April 2005
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 1	Dated 19 April 2005
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 2	Dated 14 November 2006
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 3	Dated 12 March 2009

Following completion of Requirement 2, no further action is required and compliance with this AD is complete.

Note 2:  Requirement 2 is only applicable if required by Requirement 1.b.iii.A. and Requirement 1.b.iv of this AD.

Note 3:  For ADGs specified in Requirement 1.b.iii.A repeat fluorescent penetrant inspections (per Hamilton Sundstrand SB ERPS10AG-24-3) are required as part of the periodic ADG Functional Check procedure.  Refer to Airworthiness Requirements, Part 2 of Maintenance Requirements Manual, Appendix A - Certification Maintenance Requirements (CMR) and the Aircraft Maintenance Manual (AMM), as follows:

- CMR Task No. C24-20-129-01.

- AMM Task No: 24-23-01-720-803.

Note 4:  For ADGs specified in Requirement 1.b.iii.A fluorescent penetrant inspection (per Hamilton Sundstrand SB ERPS10AG-24-3) is required following each future unscheduled in-flight ADG deployment, as specified in the following task:

- AMM Task No: 05-51-19-210-801.

Note 5:  In Hamilton Sundstrand SB ERPS10AG-24-3, the fluorescent penetrant inspection is referred to as a “Penetrant Check”.

b.    Applicable to CL-600-2C10 Aircraft, S/Ns 10003 through 10260, and
CL-600-2D15 and CL-600-2D24 Aircraft, S/Ns 15001 through 15106:

Inspect the ADG strut, and replace the ADG as necessary, in accordance with the Accomplishment Instructions in Bombardier Alert Service Bulletin (ASB) A670BA-24-020, Revision C, dated 20 April 2009, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Prior accomplishment of the fluorescent penetrant inspection, conducted in accordance with either the above referenced SB or one of the SBs listed in Table 2, also meets the intent of Requirement 2 of this AD.

Table 2

Bombardier Alert SB A670BA-24-020	Original Issue	Dated 20 April 2005
Bombardier Alert SB A670BA-24-020	Revision A	Dated 17 May 2005

Bombardier Alert SB A670BA-24-020	Revision B	Dated 7 December 2006
Hamilton Sundstrand SB ERPS10AG-24-3	Original Issue	Dated 14 April 2005
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 1	Dated 19 April 2005
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 2	Dated 14 November 2006
Hamilton Sundstrand SB ERPS10AG-24-3	Revision 3	Dated 12 March 2009

Following completion of Requirement 2, no further action is required and compliance with this AD is complete.

Note 6:  Requirement 2 is only applicable if required by Requirement 1.b.iii.A. and Requirement 1.b.iv of this AD.

Note 7:  For ADGs specified in Requirement 1.b.iii.A repeat fluorescent penetrant inspections (per Hamilton Sundstrand SB ERPS10AG-24-3) are required as part of the periodic ADG Functional Check procedure. Refer to Airworthiness Requirements, Part 2 of Maintenance Requirements Manual, Appendix A - Certification Maintenance Requirements (CMR) and the Aircraft Maintenance Manual (AMM), as follows:

- CMR Task No. 24-23-00-102.

- AMM Task No: 24-23-01-720-802.

Note 8:  For ADGs specified in Requirement 1.b.iii.A  fluorescent penetrant inspection (per Hamilton Sundstrand SB ERPS10AG-24-3) is required following each future unscheduled in-flight ADG deployment, as specified in the following task:

- AMM Task No: 05-51-19-210-801.

Note 9:  In Hamilton Sundstrand SB ERPS10AG-24-3, the fluorescent penetrant inspection is referred to as a “Penetrant Check”.

Note 10:  Transport Canada AD CF-2009-27 dated 8 June 2009 refers.

Compliance:

For Requirements 1 and 2 - Within 1,000 flight hours or before the next scheduled ADG functional check, whichever comes first, after the effective date of this AD.

This Airworthiness Directive becomes effective on 27 August 2009.

Background:

Two cases of a crack on a "dry" ADG (Hamilton Sundstrand part number in the 761339 series), in the aft area of the strut and generator housing assembly, have been reported on CL-600-2B19 aircraft.  The same part is also installed on CL-600-2C10, -2D15 and -2D24 aircraft.  Investigation determined that the crack was in an area of the strut where the wall thickness of the casting was below specification, due to a manufacturing anomaly in a specific batch of ADGs.  Structural failure and departure of the ADG during deployment could possibly result in damage to the aircraft structure.  If deployment was activated by a dual engine shutdown, ADG structural failure would also result in loss of hydraulics for the flight controls.

James Coyne
Delegate of the Civil Aviation Safety Authority

15 July 2009