AD 74-22-06

final rule

Airworthiness Directives; de Havilland Model DHC-6 Airplanes

AD Number
74-22-06
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
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

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AD Final Rules - DRS_74-22-06.html
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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

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