AD 59-06-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion B | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion D | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
Unsafe Condition
Failures of hydraulic actuating cylinders causing loss of flaps and landing gear collapse.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect flap and landing gear actuating cylinders for cracks and replace if any are found. Adjust hydraulic system pressure relief valve to 1125+25, -0 p.s.i. Install hydraulic fluid restrictors in nose gear lines (Serial Numbers 1271 and subsequent), main gear lines (Serial Numbers 1790 and subsequent), and flap lines (all serial numbers). Inspect linkage adjustments of landing gear bungee springs and flap stops to ensure proper alignment per service manuals.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
by May 1, 1959, and at each periodic inspection thereafter
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Affected Aircraft
Tusco Corporation Navion models: Navion (Army L-17A), Navion A (Army L-17B and L-17C), Navion B, Navion D, with serial number ranges specified for restrictors: nose gear lines (1271 and subsequent), main gear lines (1790 and subsequent), and flap lines (all serial numbers)
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Hydraulic Actuating Cylinders
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_59-06-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-06-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models Subject: Hydraulic Actuating Cylinders 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 | Navion D 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: 59-06-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-06-04 SUBJECT HEADING: Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-06-04 NAVION: Tusco Corporation (Navion) Applies to All Models. Several failures of hydraulic actuating cylinders have occurred causing the loss of the use of the flaps and the landing gear to collapse. To prevent further difficulties of this nature, the following items must be accomplished by May 1, 1959, and at each periodic inspection thereafter. (1) Inspect the flap and landing gear actuating cylinders for cracks. If any cracks appear, the cylinder must be replaced. (2) Determine, by means of a hydraulic gage, that the hydraulic system pressure relief valve is adjusted to 1125+25, -0 p.s.i. Excessive pressures could cause damage to the components of the system. (3) Hydraulic fluid restrictors are required in the nose gear lines, Serial Numbers 1271 and subsequent, main gear lines, Serial Numbers 1790 and subsequent, and flap lines, all serial numbers. (4) Inspect the linkage adjustments of the landing gear bungee springs and the flap stops and determine that they have been properly adjusted in accordance with appropriate service manuals. (Tusco Corporation Service Letter No. 79 dated December 23, 1958, covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_59-06-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-06-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models Subject: Hydraulic Actuating Cylinders 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 | Navion D 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: 59-06-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-06-04 SUBJECT HEADING: Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-06-04 NAVION: Tusco Corporation (Navion) Applies to All Models. Several failures of hydraulic actuating cylinders have occurred causing the loss of the use of the flaps and the landing gear to collapse. To prevent further difficulties of this nature, the following items must be accomplished by May 1, 1959, and at each periodic inspection thereafter. (1) Inspect the flap and landing gear actuating cylinders for cracks. If any cracks appear, the cylinder must be replaced. (2) Determine, by means of a hydraulic gage, that the hydraulic system pressure relief valve is adjusted to 1125+25, -0 p.s.i. Excessive pressures could cause damage to the components of the system. (3) Hydraulic fluid restrictors are required in the nose gear lines, Serial Numbers 1271 and subsequent, main gear lines, Serial Numbers 1790 and subsequent, and flap lines, all serial numbers. (4) Inspect the linkage adjustments of the landing gear bungee springs and the flap stops and determine that they have been properly adjusted in accordance with appropriate service manuals. (Tusco Corporation Service Letter No. 79 dated December 23, 1958, 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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