AD 54-18-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; All Navion Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; All Navion Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion B | Airworthiness Directives; All Navion Models |
Unsafe Condition
Relative motion between the wing and fuselage at the wing-to-fuselage attachment due to elongated bolt holes, necessitating additional shear carrying attachment angles.
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Required Actions
Inspect for looseness at six bolt locations; ream holes and replace bolts if elongated, install doubler strips on frame 142.57 if aft bolts are loose, and install alclad angles for chordwise shear attachment. Corrective actions must be completed immediately if looseness is found, otherwise by next annual inspection.
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Compliance Time
As soon as practicable but not later than October 15, 1954. If no looseness detected, corrective actions may be delayed until the next annual inspection.
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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.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Wing-to-Fuselage Attachment
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_54-18-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 54-18-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; All Navion Models Subject: Wing-to-Fuselage Attachment 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L-17A) | Navion A (Army L-17B and L-17C) | Navion B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 54-18-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 54-18-01 SUBJECT HEADING: Airworthiness Directives; All Navion Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 54-18-01 NAVION: Applies to All Models. Compliance required as indicated. Inspection of a number of Navions has revealed an undesirable condition in which there is relative motion between the wing and fuselage at the wing-to-fuselage attachment necessitating installation of additional shear carrying attachment angles between the fuselage and wing. This condition is most prevalent in, but not limited to, older Navions and can be readily detected when the wing root fillets have been removed and a sharp fore and aft shaking force is applied to the wing tip. If loose, the applied force can be made to develop a motion of the wing mass which is opposite to the motion of the fuselage mass, and the looseness will be definitely seen and felt. It is therefore necessary that all Navions be inspected for this condition as soon as practicable but not later than October 15, 1954. In case the wings and fuselage seem to move as a unit mass and feel "solid" to the person applying the force, the corrective action outlined below may be delayed until the next annual inspection of the airplane. If a loose condition is evident, immediate corrective action as indicated in items 1 and 2 is necessary. 1. Determine whether there is any looseness due to elongated holes at the six bolt locations (two outboard and two inboard forward wing attachment bolts and two aft wing attachment bolts). If no elongated holes are found, the corrective action in item 2 should be accomplished. If elongated holes are evident proceed as follows (including item 2): (a) Ream each of the four forward wing attachment bolt holes (AN 5 inboard and AN 6 outboard) to receive the next larger size bolts. Remove and replace only one bolt at a time and torque to 140 inch-pounds. (If the next larger size bolts had already been installed previously for other reasons, the rework in accordance with this directive should be brought to the attention of the local FAA Agent for detail consideration. (b) Remove the two AN 5-65A aft attachment bolts, tube spacers, washers and units and install two 4 1/2-inch long 0.064 24ST alclad doubler strips to each end of the bottom inside flange of frame 142.57. Rivet each strip to the frame with four 5/32-diameter rivets and drill and ream to 0.3125-diameter to match the existing 5/16-diameter bolt hole in each frame. The two tube spacers must be shortened to fit within the channel and the two AN 5-65A bolts should be installed and torqued to 140 inch-pounds. 2. Install the following wing-to-fuselage chordwise shear attachment. (a) An 0.064 24S-T4 alclad angle should be fabricated to conform to the wing contour and attached to the lower longeron, inboard flange (both sides of airplanes). This angle should extend from the wing front spar reference plane to approximately 1 inch aft of the wing center spar reference plane (approximately 22 1/2 inches long). Attachment to the upper longeron should be made with eight AN 3 bolts. Attachment to the wing skin should be with fifteen 5/32 rivets (may be blind). Caution should be used in drilling through the wing skin to avoid injuring the fuel tank. (b) Flange of angle attaching to wing skin may be cut to conform to existing holes in wing skin for tubing which may pass through this area. (Ryan Navion Field Service Bulletin No. 21 covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_54-18-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 54-18-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; All Navion Models Subject: Wing-to-Fuselage Attachment 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: 54-18-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 54-18-01 SUBJECT HEADING: Airworthiness Directives; All Navion Models ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 54-18-01 NAVION: Applies to All Models. Compliance required as indicated. Inspection of a number of Navions has revealed an undesirable condition in which there is relative motion between the wing and fuselage at the wing-to-fuselage attachment necessitating installation of additional shear carrying attachment angles between the fuselage and wing. This condition is most prevalent in, but not limited to, older Navions and can be readily detected when the wing root fillets have been removed and a sharp fore and aft shaking force is applied to the wing tip. If loose, the applied force can be made to develop a motion of the wing mass which is opposite to the motion of the fuselage mass, and the looseness will be definitely seen and felt. It is therefore necessary that all Navions be inspected for this condition as soon as practicable but not later than October 15, 1954. In case the wings and fuselage seem to move as a unit mass and feel "solid" to the person applying the force, the corrective action outlined below may be delayed until the next annual inspection of the airplane. If a loose condition is evident, immediate corrective action as indicated in items 1 and 2 is necessary. 1. Determine whether there is any looseness due to elongated holes at the six bolt locations (two outboard and two inboard forward wing attachment bolts and two aft wing attachment bolts). If no elongated holes are found, the corrective action in item 2 should be accomplished. If elongated holes are evident proceed as follows (including item 2): (a) Ream each of the four forward wing attachment bolt holes (AN 5 inboard and AN 6 outboard) to receive the next larger size bolts. Remove and replace only one bolt at a time and torque to 140 inch-pounds. (If the next larger size bolts had already been installed previously for other reasons, the rework in accordance with this directive should be brought to the attention of the local FAA Agent for detail consideration. (b) Remove the two AN 5-65A aft attachment bolts, tube spacers, washers and units and install two 4 1/2-inch long 0.064 24ST alclad doubler strips to each end of the bottom inside flange of frame 142.57. Rivet each strip to the frame with four 5/32-diameter rivets and drill and ream to 0.3125-diameter to match the existing 5/16-diameter bolt hole in each frame. The two tube spacers must be shortened to fit within the channel and the two AN 5-65A bolts should be installed and torqued to 140 inch-pounds. 2. Install the following wing-to-fuselage chordwise shear attachment. (a) An 0.064 24S-T4 alclad angle should be fabricated to conform to the wing contour and attached to the lower longeron, inboard flange (both sides of airplanes). This angle should extend from the wing front spar reference plane to approximately 1 inch aft of the wing center spar reference plane (approximately 22 1/2 inches long). Attachment to the upper longeron should be made with eight AN 3 bolts. Attachment to the wing skin should be with fifteen 5/32 rivets (may be blind). Caution should be used in drilling through the wing skin to avoid injuring the fuel tank. (b) Flange of angle attaching to wing skin may be cut to conform to existing holes in wing skin for tubing which may pass through this area. (Ryan Navion Field Service Bulletin No. 21 covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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