AD 80-26-03
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking Air Limited | DHC-4 | Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft |
| aircraft | Viking Air Limited | DHC-4A | Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft |
Unsafe Condition
Failure of the left hand magneto drive mechanism
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Incorporate the right-hand magneto drive and associated parts as described in Pratt & Whitney Aircraft Service Bulletin No. 1756 or approved equivalent instructions and parts. Redesignate the engines as noted in Section C of the service bulletin.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 1400 hours in service after the effective date of this AD unless already accomplished
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Affected Aircraft
DeHavilland Model DHC-4 and DHC-4A aircraft equipped with Pratt & Whitney Aircraft Twin Wasp D-5 and R-2000-7M2 engines incorporating left-hand magneto drive arrangement
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Magneto Drive Mechanism
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_80-26-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-26-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft Subject: Magneto Drive Mechanism Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/19/1980 Make: Viking Air Limited Model: DHC-4 | DHC-4A Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-26-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3993 AD NUMBER: 80-26-03 SUBJECT HEADING: Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft ACTION: SUMMARY: DATES: Effective December 19, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-26-03 DEHAVILLAND: Amendment 39-3993. Applies to all DeHavilland DHC-4 and DHC-4A aircraft equipped with Pratt & Whitney Aircraft Twin Wasp D-5 and R-2000-7M2 engines incorporating left-hand magneto drive arrangement. Compliance required within the next 1400 hours in service after the effective date of this AD unless already accomplished. To preclude failure of the left hand magneto drive mechanism, incorporate the right-hand magneto drive and associated parts as described in Pratt & Whitney Aircraft Service Bulletin No. 1756 dated September 13, 1963, or approved equivalent instructions and parts. The Twin Wasp D-5 and R-2000-7M2 engines so modified must be redesignated as noted in Section C of the Pratt & Whitney Aircraft Service Bulletin No. 1756, or an approved equivalent instruction. All equipment instructions and parts must be approved by the Chief, Engineering & Manufacturing Branch, FAA Eastern Region. (Pratt & Whitney Aircraft Service Bulletin No. 1756 pertains to this subject.) This amendment is effective December 19, 1980. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_80-26-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-26-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft Subject: Magneto Drive Mechanism Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/19/1980 Make: Viking Air Limited Model: DHC-4 | DHC-4A Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-26-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3993 AD NUMBER: 80-26-03 SUBJECT HEADING: Airworthiness Directives; DeHavilland Model DHC-4 and DHC-4A Aircraft ACTION: SUMMARY: DATES: Effective December 19, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-26-03 DEHAVILLAND: Amendment 39-3993. Applies to all DeHavilland DHC-4 and DHC-4A aircraft equipped with Pratt & Whitney Aircraft Twin Wasp D-5 and R-2000-7M2 engines incorporating left-hand magneto drive arrangement. Compliance required within the next 1400 hours in service after the effective date of this AD unless already accomplished. To preclude failure of the left hand magneto drive mechanism, incorporate the right-hand magneto drive and associated parts as described in Pratt & Whitney Aircraft Service Bulletin No. 1756 dated September 13, 1963, or approved equivalent instructions and parts. The Twin Wasp D-5 and R-2000-7M2 engines so modified must be redesignated as noted in Section C of the Pratt & Whitney Aircraft Service Bulletin No. 1756, or an approved equivalent instruction. All equipment instructions and parts must be approved by the Chief, Engineering & Manufacturing Branch, FAA Eastern Region. (Pratt & Whitney Aircraft Service Bulletin No. 1756 pertains to this subject.) This amendment is effective December 19, 1980. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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