AD/DHC-8/122 Engine Exhaust Shroud V-band Coupling (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-8/122 | Engine Exhaust Shroud V-band Coupling | 7/2006 |
Applicability: | Bombardier Inc. Model DHC-8-400, DHC-8-401 and DHC-8-402 Serial Numbers 4001 through 4098 with engine exhaust shroud V-band clamps (part numbers VC1642A-1875-A or VC1642A-2030-A) that have manufacturer batch stamp dated earlier than 08 02 (August 2002). |
Requirement: | Unless previously accomplished carry out an inspection and replacement (as required) of the V-band clamps to ensure a proper gap, in accordance with Bombardier SB Note: Transport Canada AD CF-2006-06 dated 4 April 2006 refers. |
Compliance: | Within 5000 flight hours after the effective date of this AD. |
| This Airworthiness Directive becomes effective on 6 July 2006. | |
Background: | There have been reports of a discrepancy on a V-band clamp located on the engine exhaust duct shroud during maintenance inspections. The clamp ends were found touching with the correct fastener torque applied, resulting in reduced clamp force on the flanges. Investigation revealed that a batch of V-band clamps was not manufactured to the drawing specifications. If not corrected, this condition may cause vibration and fretting of the V-band clamp flanges, leading to flange cracking and local area overheating. This situation can trigger the fire warning system and result in an in-flight emergency such as the flight crew requiring to shut down the engine and activate the fire suppression system. |
James Coyne
Delegate of the Civil Aviation Safety Authority
24 May 2006
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