AD 2019-10-05 Airworthiness Directives; Viking Air Limited (Type Certificate Previously Held by Bombardier Inc.; de Havilland, Inc.) Airplanes

Models named: DHC-6-1, DHC-6-100, DHC-6-200, DHC-6-300, DHC-6-400. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Viking Air Limited (type certificate previously held by Bombardier Inc.; de Havilland, Inc.) Models DHC-6-1, DHC-6-100, DHC-6-200, DHC-6-300, and DHC-6-400 airplanes, all serial numbers, certificated in any category.

Unless already done, do the following actions in paragraphs (f)(1) and (2) of this AD. (1) Within the next 90 days after the effective date of this AD or upon reaching the life limit for replacing an elevator or rudder control cable, whichever occurs first, inspect the cables for abnormal wear at pulley location STA 270.3. If there is abnormal wear on a cable, before further flight, in addition to replacing the life-limited cable from service, replace the corresponding pulley. For purposes of this AD, abnormal wear is defined as either of the following: (i) Wear on an individual wire exceeding 40 percent of the original wire size or the blending of worn areas on the adjacent wires exceeding 40 percent; or (ii) More than three broken wires in a one-inch span of 7 × 7 cable or six broken wires in a one-inch span of 7 × 19 cable. (2) Within the next 90 days after the effective date of this AD, revise the Airworthiness Limitations section of your maintenance program by adding the following requirements: (i) At the scheduled replacement of each life-limited elevator and rudder control cable, inspect the cable for abnormal wear at pulley location STA 270.3. (ii) If there is abnormal wear on the cable at the pulley location, before further flight, in addition to removing the life-limited cable from service, replace the corresponding pulley.

The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, New York ACO Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone: (516) 228-7300; fax: (516) 794-5531; email: 9-avs-nyaco-cos@faa.gov . Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. (2) Contacting the Manufacturer: For any requirement in this AD to obtain corrective actions from a manufacturer, the action must instead be accomplished using a method approved by the Manager, New York ACO Branch, FAA; or Transport Canada Civil Aviation (TCCA); or Viking Air Limited's Design Organization Approval (DOA). If approved by the DOA, the approval must include the DAO-authorized signature.

This AD was prompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as occurrences of excessive wear of elevator cables at pulley location station (STA) 270.3. The FAA is issuing this AD to prevent failure of the elevator and rudder control cables, which could result in loss of control of the airplane.

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