De Havilland DHC 2 - Service Difficulty Alert

AL 2004-08
29 December 2004

Unapproved Rudder Pedal Torque Tube

Transport Canada has been notified through the Service Difficulty Reporting Program (SDR), of the failure of the rudder pedal mount assembly on a DHC-2 "Beaver" aircraft. During take-off, the rudder pedal mount assembly, P/N C2CF1777A, failed at the base of the operating lever, allowing the right rudder pedal to drop to the floor. Rudder control was lost and the take-off aborted.

Upon examination of the affected parts, it was noted that the weld had separated cleanly from the tube; all weld filler material remained on the operating lever half.

This torque tube assembly is difficult to inspect at the weld location unless the foot well panel is removed to enable viewing from above.


Failed, Unapproved Part - Incomplete weld and missing stiffener

A thorough investigation by the original equipment manufacturer (OEM) determined the following:

  1. The gusset attached originally to the tube was slightly bent, indicating that it was most probably forced into its position. Furthermore, the welded portion revealed that the gusset had detached itself from the tube.
  2. There was a lack of fusion at the root of the welded portion of the gusset.
  3. The mating surface (tube), which was welded to the gusset, exhibited a fracture surface that resembles more of a brazing operation rather than a weld.


Approved Part - Note: Circumferential weld and stiffener installation

Based on these and other findings, the OEM has determined this part was not manufactured as per the approved drawing, C2CF1777A, and is in fact an "unapproved" or "bogus" part.

Transport Canada strongly recommends owners and operators of this aircraft inspect, at their earliest convenience, the rudder pedal torque tube assembly, to ensure conformance to the original specification. This can be accomplished by checking for circumferential weld on both the gusset and the pedal arm lever attachment point.

Further assistance in determining the conformity of the part is available from the Bombardier customer support center (CSC) help desk:

Tel: (514) 855-8900 
Fax: (514) 956-2888 

Similar defects or further occurrences of this nature are to be reported to Transport Canada, Continuing Airworthiness, Ottawa, via the Service Difficulty Reporting program.

For further information contact a Transport Canada Center, or Mr. Paul Jones, Continuing Airworthiness, Ottawa, telephone (613) 952-4431, facsimile (613) 996-9178 or e-mail

For Director, Aircraft Certification

B. Goyaniuk
Chief, Continuing Airworthiness

Note: For the electronic version of this document, please consult the following Web address: