AD 90-24-10
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking Air Limited | DHC-7-1 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 Series Airplanes |
| aircraft | Viking Air Limited | DHC-7-100 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 Series Airplanes |
| aircraft | Viking Air Limited | DHC-7-101 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 Series Airplanes |
| aircraft | Viking Air Limited | DHC-7-102 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 Series Airplanes |
| aircraft | Viking Air Limited | DHC-7-103 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 Series Airplanes |
Unsafe Condition
Corrosion and reduced structural capability of the wings due to inboard and outboard fuel tank lower wing skins.
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Required Actions
Within 180 days after the effective date, perform a low frequency eddy current inspection of the inboard and outboard fuel tank lower wing skins every year. If corrosion is found, remove fuel tank foam blocks, restore corroded areas, and modify stringers per Service Bulletin 7-57-33. If no corrosion, remove inboard foam blocks and modify stringers within three years. Alternate compliance may be approved by the FAA.
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Compliance Time
Within 180 days after the effective date of this AD, and thereafter at intervals not to exceed one year
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Affected Aircraft
Boeing Of Canada, Ltd., De Havilland Division Model DHC-7 series airplanes, Serial Numbers 1 through 10, and 12 through 27
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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