Airworthiness Directive · Amendment 39-22041 · Flight control system
Viking Air Limited (Type Certificate Previously Held by Bombardier, Inc. and de Havilland, Inc.) Airplanes
This AD applies to Viking Air Limited (type certificate previously held by Bombardier, Inc. and de Havilland, Inc.) Model DHC-6-1, DHC-6-100, DHC-6-200, DHC-6-300, and DHC-6-400 airplanes, serial numbers 001 through 987, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for certain Viking Air Limited (type certificate previously held by Bombardier, Inc. and de Havilland, Inc.) Model DHC-6-1, DHC-6-100, DHC- 6-200, DHC-6-300, and DHC-6-400 airplanes. This AD was prompted by mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI identifies the unsafe condition as loose quadrants on the rudder pedal torque tube and signs of loose rivets or rivet joint wear due to inadequate manufacturing tolerances. This AD requires inspecting the rudder pedal torque tube quadrant for looseness and taking corrective action as necessary. The FAA is issuing this AD to address the unsafe condition on these products.
Within 3 months after the effective date of this AD, inspect the rudder pedal torque tube quadrant assembly for looseness and, if there is any looseness of the rudder pedal torque tube quadrant assembly, a loose rivet, any rivet joint wear, or a smoking rivet, before further flight, repair or replace the rudder pedal torque tube or quadrant assembly. Do these actions by following the Accomplishment Instructions, steps A.1. through A.9., in Viking DHC-6 Twin Otter Service Bulletin No. V6/0067, Revision A, dated January 26, 2021, except for any requirement to obtain repair instructions from Viking Customer Support, the repair must be accomplished using a method approved by the Manager, New York ACO Branch, FAA; Transport Canada; or Viking Air Limited's Transport Canada Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.
