AD 56-03-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; Navion All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; Navion All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion B | Airworthiness Directives; Navion All Models |
Unsafe Condition
Cracks starting at the wing centerline attaching bolt hole in the wing rear spar junction fittings (P/N 145-14070) at wing Station O have been found on a number of Navion aircraft.
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Required Actions
Inspect all Navions for cracks as soon as practicable but not later than May 1, 1956. If no cracks are found, install 3/16-inch thick 1010 steel end plates prior to the next 50 hours of flight time. If cracks are found, stop-drill them with a No. 60 drill (0.040 inch) and install the end plates prior to the next flight.
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Compliance Time
as soon as practicable but not later than May 1, 1956
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Affected Aircraft
Sierra Hotel Aero, Inc. Navion (Army L-17A), Navion A (Army L-17B and L-17C), Navion B models
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Federal Register Abstract
Wing Rear Spar Fitting Inspection
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_56-03-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-03-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion All Models Subject: Wing Rear Spar Fitting Inspection 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L-17A) | Navion A (Army L-17B and L-17C) | Navion B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 56-03-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-03-03 SUBJECT HEADING: Airworthiness Directives; Navion All Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-03-03 NAVION: Applies to All Models. Compliance required as indicated. Cracks starting at the wing centerline attaching bolt hole in the wing rear spar junction fittings (P/N 145-14070) at wing Station O have been found on a number of Navion aircraft. To correct this, it will be necessary to inspect all Navions for this condition as soon as practicable but not later than May 1, 1956. Access to these fitting may be gained through the main wheel wells. If no cracks are found, 3/16-inch thick 1010 steel (or equivalent) end plates, properly radiused for a snug fit, should be installed in each fitting prior to the next 50 hours of flight time. If cracks are found, they should be stop-drilled with a No. 60 (0.040 drill and the end plates as described above should be installed prior to the next flight. No further inspections will be necessary upon installation of these end plates. (Ryan Navion Service Bulletin No. 23 dated December 5, 1955, covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_56-03-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-03-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion All Models Subject: Wing Rear Spar Fitting Inspection 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: 56-03-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-03-03 SUBJECT HEADING: Airworthiness Directives; Navion All Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-03-03 NAVION: Applies to All Models. Compliance required as indicated. Cracks starting at the wing centerline attaching bolt hole in the wing rear spar junction fittings (P/N 145-14070) at wing Station O have been found on a number of Navion aircraft. To correct this, it will be necessary to inspect all Navions for this condition as soon as practicable but not later than May 1, 1956. Access to these fitting may be gained through the main wheel wells. If no cracks are found, 3/16-inch thick 1010 steel (or equivalent) end plates, properly radiused for a snug fit, should be installed in each fitting prior to the next 50 hours of flight time. If cracks are found, they should be stop-drilled with a No. 60 (0.040 drill and the end plates as described above should be installed prior to the next flight. No further inspections will be necessary upon installation of these end plates. (Ryan Navion Service Bulletin No. 23 dated December 5, 1955, covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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Related Airworthiness Directives
2008-05-14 Recurring
final ruleAirworthiness Directives; Sierra Hotel Aero, Inc. Models Navion (L-17A), Navion A (L-17B), (L-17C), Navion B, Navion D, Navion E, Navion F, Navion G, and Navion H Airplanes
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62-03-03
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47-31-03
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