AD 87-04-23
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking Air Limited | DHC-6-1 | Airworthiness Directives; DeHavilland DHC-6-1, DHC-6- 100, DHC-6-200, and DHC-6-300 Series Airplanes |
| aircraft | Viking Air Limited | DHC-6-100 | Airworthiness Directives; DeHavilland DHC-6-1, DHC-6- 100, DHC-6-200, and DHC-6-300 Series Airplanes |
| aircraft | Viking Air Limited | DHC-6-200 | Airworthiness Directives; DeHavilland DHC-6-1, DHC-6- 100, DHC-6-200, and DHC-6-300 Series Airplanes |
| aircraft | Viking Air Limited | DHC-6-300 | Airworthiness Directives; DeHavilland DHC-6-1, DHC-6- 100, DHC-6-200, and DHC-6-300 Series Airplanes |
Unsafe Condition
Failure of the wing support struts due to corrosion.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect each wing support strut for corrosion in accordance with DeHavilland Service Bulletin 6/474. For aircraft with 5,000+ hours TIS or 4.5+ years old by AD effective date, inspect within next 1,000 hours TIS or 6 months. For others, inspect before 6,000 hours TIS or 5 years. Reinspect every 6,000 hours TIS or 5 years. Replace struts with moderate/severe corrosion or corrosion within 20 inches of ends before further flight. Remove light corrosion within 30 days.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
After the effective date of this AD (March 16, 1987), unless already accomplished.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
DeHavilland DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-300 series airplanes (all serial numbers).
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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