AD 78-01-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking Air Limited | DHC-6-1 | Airworthiness Directives; de Havilland of Canada DHC-6 Series Aircraft |
| aircraft | Viking Air Limited | DHC-6-100 | Airworthiness Directives; de Havilland of Canada DHC-6 Series Aircraft |
| aircraft | Viking Air Limited | DHC-6-200 | Airworthiness Directives; de Havilland of Canada DHC-6 Series Aircraft |
| aircraft | Viking Air Limited | DHC-6-300 | Airworthiness Directives; de Havilland of Canada DHC-6 Series Aircraft |
Unsafe Condition
Total electrical failure due to contact welding of the reverse current relay and subsequent burning of adjacent wiring, the other reverse current relay, and the battery circuit wiring.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install de Havilland modification 6/1598 in accordance with de Havilland Service Bulletin No. 6/353 dated May 13, 1977, or later revision, or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 800 hours in service after the effective date of this AD unless already accomplished, or de Havilland Modification 6/1591 is incorporated
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
de Havilland of Canada DHC-6 series aircraft serial numbers 1 through 530
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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