AD 53-08-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications |
| aircraft | Sierra Hotel Aero, Inc. | Navion B | Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications |
Unsafe Condition
Improper rivet edge distance on 145-21404-1 and -2 front fittings of the horizontal stabilizer may result in structural failure due to insufficient material extending beyond the rivet holes.
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Required Actions
Inspect both 145-21404-1 and -2 front fittings for proper rivet edge distance. If the edge distance is less than 1/16 inch, install new fittings with proper edge distance.
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Compliance Time
June 15, 1953, or next 100-hour inspection, whichever is first
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Affected Aircraft
Sierra Hotel Aero, Inc. Navion models (Army L-17A), Navion A (Army L-17B and L-17C), Navion B, except those incorporating Palo Alto Airport Co. or Symon Engineering Co. horizontal stabilizer modifications.
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Federal Register Abstract
Horizontal Stabilizer Fitting
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_53-08-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 53-08-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symo...Show more Subject: Horizontal Stabilizer Fitting Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) | Navion A (Army L-17B and L-17C) | Navion B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 53-08-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 53-08-01 SUBJECT HEADING: Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 53-08-01 NAVION: Applies to All Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications. Compliance required by June 15, 1953, or next 100-hour inspection, whichever is first. Inspect both 145-21404-1 and -2 front fittings on the horizontal stabilizer for proper rivet edge distance. If the entire outboard edge of the steel fitting extends past the outboard edge of the butt rib, no further action is required. On the other hand, if the edge of the fitting disappears behind the rib, it will be necessary to ascertain that at least 1/16 inch of material (steel fitting) extends beyond the edge of all rivet holes. Whenever the edge distance is found to be less than 1/16 inch, a new fitting should be installed with proper edge distance. (A method of conducting the above inspection is described in Ryan Field Service Bulletin No. 19, dated February 16, 1953, which covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_53-08-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 53-08-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symo...Show more Subject: Horizontal Stabilizer Fitting Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) | Navion A (Army L-17B and L-17C) | Navion B 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: 53-08-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 53-08-01 SUBJECT HEADING: Airworthiness Directives; All Navion Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 53-08-01 NAVION: Applies to All Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications. Compliance required by June 15, 1953, or next 100-hour inspection, whichever is first. Inspect both 145-21404-1 and -2 front fittings on the horizontal stabilizer for proper rivet edge distance. If the entire outboard edge of the steel fitting extends past the outboard edge of the butt rib, no further action is required. On the other hand, if the edge of the fitting disappears behind the rib, it will be necessary to ascertain that at least 1/16 inch of material (steel fitting) extends beyond the edge of all rivet holes. Whenever the edge distance is found to be less than 1/16 inch, a new fitting should be installed with proper edge distance. (A method of conducting the above inspection is described in Ryan Field Service Bulletin No. 19, dated February 16, 1953, which covers this same 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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