AD 74-22-06
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Viking Air Limited | DHC-6-1 | Airworthiness Directives; de Havilland Model DHC-6 Airplanes |
| aircraft | Viking Air Limited | DHC-6-100 | Airworthiness Directives; de Havilland Model DHC-6 Airplanes |
| aircraft | Viking Air Limited | DHC-6-200 | Airworthiness Directives; de Havilland Model DHC-6 Airplanes |
| aircraft | Viking Air Limited | DHC-6-300 | Airworthiness Directives; de Havilland Model DHC-6 Airplanes |
Unsafe Condition
Cracks in the horizontal stabilizer rear spars at the junctions of the spar webs with the top and bottom flanges between Stations 10.00 and 53.00.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect visually using a magnification glass of at least 10 power or an approved equivalent for spanwise cracks. If cracks are found, alter the spar per paragraph 2 of Service Bulletin 6/310 or approved equivalent before further flight. Equivalent inspections or alterations require approval from 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 the next 50 hours in service or 1 week, whichever occurs first, after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
de Havilland Model DHC-6 airplanes, Serial Numbers 1 to 393 inclusive excluding 107, 168, 182, 184, 209, 383, 385, 386, 390, and 391
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Horizontal Stabilizer
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_74-22-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 74-22-06 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; de Havilland Model DHC-6 Airplanes Subject: Horizontal Stabilizer Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/23/1974 Make: Viking Air Limited Model: DHC-6-1 | DHC-6-100 | DHC-6-200 | DHC-6-300 Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 74-22-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1993 AD NUMBER: 74-22-06 SUBJECT HEADING: Airworthiness Directives; de Havilland Model DHC-6 Airplanes ACTION: SUMMARY: DATES: Effective October 23, 1974. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 74-22-06 DEHAVILLAND: Amendment 39-1993. Applies to DHC-6 airplanes Serial Numbers 1 to 393 inclusive, excluding Serial Numbers 107, 168, 182, 184, 209, 383, 385, 386, 390 and 391, certificated in all categories. To detect cracks in the horizontal stabilizer rear spars, within the next 50 hours in service or 1 week, whichever occurs first, after the effective date of this AD, unless already accomplished, inspect visually using a magnification glass of at least 10 power or an approved equivalent for spanwise cracks along the radii at the junctions of the rear spar webs with the top and bottom flanges between Station 10.00 and Station 53.00 on the left and right hand horizontal stabilizers. If cracks are found, accomplish the following: 1. Alter the spar in accordance with paragraph 2 of Accomplishment Instructions of de Havilland Service Bulletin No. 6/310, dated June 28, 1974, or an approved equivalent before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the alteration can be performed. 2. Equivalent inspections or alterations must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. 3. The compliance times may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, upon receipt of substantiating data submitted through an FAA maintenance inspector. This amendment is effective October 23, 1974. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_74-22-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 74-22-06 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; de Havilland Model DHC-6 Airplanes Subject: Horizontal Stabilizer Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/23/1974 Make: Viking Air Limited Model: DHC-6-1 | DHC-6-100 | DHC-6-200 | DHC-6-300 Product Type: Aircraft Product Subtype: Small 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: 74-22-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1993 AD NUMBER: 74-22-06 SUBJECT HEADING: Airworthiness Directives; de Havilland Model DHC-6 Airplanes ACTION: SUMMARY: DATES: Effective October 23, 1974. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 74-22-06 DEHAVILLAND: Amendment 39-1993. Applies to DHC-6 airplanes Serial Numbers 1 to 393 inclusive, excluding Serial Numbers 107, 168, 182, 184, 209, 383, 385, 386, 390 and 391, certificated in all categories. To detect cracks in the horizontal stabilizer rear spars, within the next 50 hours in service or 1 week, whichever occurs first, after the effective date of this AD, unless already accomplished, inspect visually using a magnification glass of at least 10 power or an approved equivalent for spanwise cracks along the radii at the junctions of the rear spar webs with the top and bottom flanges between Station 10.00 and Station 53.00 on the left and right hand horizontal stabilizers. If cracks are found, accomplish the following: 1. Alter the spar in accordance with paragraph 2 of Accomplishment Instructions of de Havilland Service Bulletin No. 6/310, dated June 28, 1974, or an approved equivalent before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the alteration can be performed. 2. Equivalent inspections or alterations must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. 3. The compliance times may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, upon receipt of substantiating data submitted through an FAA maintenance inspector. This amendment is effective October 23, 1974. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.