AD/CL-600/78 Amdt 1 Engine Throttle Control Gearbox (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/CL-600/78 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.

Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes

AD/CL-600/78 Amdt 1 Engine Throttle Control Gearbox 21/2009

Applicability:

All Bombardier Inc. model CL-600-2B19 aircraft that have engine Throttle Control Gearbox (TCGB) Part Number (P/N): 2100140-003 or 2100140-005 or P/N 2100140-007 installed.

Requirement:

Update the CL-600-2B19 Maintenance Requirements Manual (MRM) document (CSP A-053) to incorporate the Temporary Revision (TR) 2A-47 for compliance with CMR Task # C76-11-127-01 requirements.

Note:  Transport Canada AD CF-2004-01R2 dated 29 September 2009 refers.

Compliance:

Within 30 days from the effective date of this AD.

This Amendment becomes effective on 15 October 2009.

Background:

There have been numerous reported failures of the Regional Jet engine TCGB P/Ns: 2100140-003, 2100140-005 & 2100140-007.  Some of these failures have resulted in in-flight engine shutdowns.  Post incident investigations revealed that excessive wear within the engine TCGB could alter the rigging position or cause the throttle to jam.

With the rigging position altered, movement of the throttle lever towards the idle position can result in throttle moving too close to the fuel shut-off position, which potentially, can cause the engine to flame out.

Bombardier issued Service Bulletin (SB) 601R-76-019 dated 21 August 2003, to introduce an inspection of, and if required, replacement of the throttle control gearbox with a serviceable unit.  This AD was originally issued to mandate the subject inspection requirement as per SB 601R-76-019 and subsequent revisions.

The subject TCGB inspection requirements mandated as per the earlier versions of this AD are now transcribed in a new Certification Maintenance Requirement (CMR) task.

This amendment is issued to mandate the incorporation of the new CMR task into the CL-600-2B19 MRM, as introduced by the MRM TR 2A-47.

The original issue of this AD became effective on 30 August 2007.

David Villiers
Delegate of the Civil Aviation Safety Authority

9 October 2009