AD 2007-20-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking | Air Limited Model DHC-7 | Airworthiness Directives; Viking Air Limited Model DHC-7 Airplanes |
Unsafe Condition
Some SM-200 servo drive units (power servo motor and housing assemblies) installed on Model DHC-7 airplanes are not in configuration MOD H, which prevents the internal clutch fasteners from backing out. This could lead to internal clutch fasteners backing out, causing an inadvertent servo engagement and reduced controllability of the airplane.
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Required Actions
Inspect the SM-200 power servo motor and housing assembly, part numbers 4006719-904, -913, and -933, to determine if MOD H is marked. Before further flight, perform all applicable related investigative action and modifications of the power servo motor and housing assembly, in accordance with Viking Alert Service Bulletin 7-22-20, dated May 29, 2006.
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Compliance Time
Within 12 months after the effective date of this AD
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Affected Aircraft
All Viking Air Limited Model DHC-7-1, DHC-7-100, DHC-7-101, DHC-7-102, and DHC-7-103 airplanes, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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