AD/DHC-8/106 Control Column Torque Tube Rivets (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-8/106 Control Column Torque Tube Rivets 2/2006

Applicability:

Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 aircraft, serial numbers 528 through 602, and 606.

Model DHC-8-400, -401, and -402 aircraft, serial numbers 4003, 4004, 4006, 4008 through 4080, and 4082.

Requirement:

1.    For Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 aircraft, serial numbers 528 through 602, and 606:

Carry out an inspection of the left and right control column torque tube assemblies to determine the rivet types installed, in accordance with Part A of the Accomplishment Instructions of Bombardier Service Bulletin (SB) 8-27-104, dated 26 October 2004, or later Transport Canada approved revision.

If any rivet is found to be of an incorrect type or the type cannot be identified, before further flight, rework the control column torque tube in accordance with Part B of the Accomplishment Instructions of SB 8-27-104, dated 26 October 2004, or later Transport Canada approved revision.

2.    For Model DHC-8-400, -401, and -402 aircraft, serial numbers 4003, 4004, 4006, 4008 through 4080, and 4082:

Carry out an inspection of the left and right control column torque tube assemblies to determine the rivet types installed, in accordance with Part A of the Accomplishment Instructions of Bombardier Service Bulletin (SB) 84-27-24 Revision A, dated 28 September 2005, or later Transport Canada approved revision.

If any rivet is found to be of an incorrect type or the type cannot be identified, before further flight, rework the control column torque tube in accordance with Part B of the Accomplishment Instructions of SB 84-27-24 Revision A, dated 28 September 2005, or later Transport Canada approved revision.

Note:  Transport Canada AD CF-2005-39 refers. 

Compliance:

Within 5,500 flight hours after 16 February 2006.

This Airworthiness Directive becomes effective on 16 February 2006.

Background: Several aircraft were found to have incorrect rivets of lower than required strength installed on the control column torque tube during production.  This condition, if not corrected, could result in shear failure of control column torque tube rivets during a jam of the pitch control circuit.  Failure of the rivets could reduce the controllability of the aircraft due to unexpected decoupling of the elevators and large unwanted deflection of the free elevator.

David Punshon
Delegate of the Civil Aviation Safety Authority

6 January 2006