AD 47-21-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; Navion Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171. |
Unsafe Condition
The cork or rubber filler strip cemented to the upper surface of the 145-42201-71 carburetor air intake scoop may become dislodged and drawn into the air induction system.
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Required Actions
Replace the filler strip with a 3 1/8-inch x 5/8-inch dural strip of 0.093-inch thickness, flush-riveted to the scoop.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
prior to August 1, 1947
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Affected Aircraft
Sierra Hotel Aero, Inc. Navion (Army L-17A) serial numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Carburetor Air Intake Scoop Filler Strip
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_47-21-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-21-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Throu...Show more Subject: Carburetor Air Intake Scoop Filler Strip Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-21-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-21-07 SUBJECT HEADING: Airworthiness Directives; Navion Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171. ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-21-07 NAVION: (Was Mandatory Note of AD-782-3.) Applies to Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171. To be accomplished prior to August 1, 1947. Some airplanes were delivered with a cork or rubber filler strip cemented to the upper surface of the 145-42201-71 carburetor air intake scoop where the scoop fits over the flange of the air mixing chamber. This strip may becomes dislodged and drawn into the air induction system. To prevent this, replace the filler strip with a 3 1/8-inch x 5/8-inch dural strip of 0.093- inch thickness, flush-riveted to the scoop. (NAA Field Service Bulletin No. 15 covers this subject.) FOOTER:
Document Text
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AD Final Rules - DRS_47-21-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-21-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Throu...Show more Subject: Carburetor Air Intake Scoop Filler Strip Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) 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: 47-21-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-21-07 SUBJECT HEADING: Airworthiness Directives; Navion Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171. ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-21-07 NAVION: (Was Mandatory Note of AD-782-3.) Applies to Serial Numbers NAV-4-10 Through 20, 22 Through 26, 28, 29, 31 Through 49, 51, 52, 55 Through 58, 60, 63, 73, 76, 79, 82 Through 84, 88 Through 95, 99 Through 104, 106, 108, 110, 112 Through 116, 120 Through 122, 124, 125, 130, 133, 141, 151, 153, 158, 163, 171. To be accomplished prior to August 1, 1947. Some airplanes were delivered with a cork or rubber filler strip cemented to the upper surface of the 145-42201-71 carburetor air intake scoop where the scoop fits over the flange of the air mixing chamber. This strip may becomes dislodged and drawn into the air induction system. To prevent this, replace the filler strip with a 3 1/8-inch x 5/8-inch dural strip of 0.093- inch thickness, flush-riveted to the scoop. (NAA Field Service Bulletin No. 15 covers this subject.) 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.
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