AD 46-11-01
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | AT-6 (SNJ-2) | Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C |
| aircraft | The Boeing Company | AT-6A (SNJ-3) | Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C |
| aircraft | The Boeing Company | AT-6B | Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C |
| aircraft | The Boeing Company | AT-6C (SNJ-4) | Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C |
| aircraft | The Boeing Company | BC-1A | Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C |
Unsafe Condition
Cracks in the inboard end of the landing gear retracting strut attachment support channel (P/N 55-14102 or 66-14102-1) at the wing outer panel joint.
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Required Actions
Inspect the inboard end of the landing gear retracting strut attachment support channel for cracks. Install doubler angles (0.062 inch-29/32 inch x 1 inch or 1 3/8 inches x 6 3/4 inches long SAE No. 4130 steel) based on crack length: less than 2 inches use 1-inch leg with AN 442-AD4 rivets; over 2 inches use 1 3/8-inch leg with two rows of rivets. Replace rivets with AN 3 bolts where applicable. Drill 1/8-inch stop holes at crack ends. Use blind rivets if wing panel is installed.
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Compliance Time
at each periodic inspection
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Affected Aircraft
North American Models BC-1A, AT-6, AT-6A, AT-6B, AT-6C (SNJ-2, SNJ-3, SNJ-4) with serial numbers below 41-34249 (Army) or 0-43692 (Navy)
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Federal Register Abstract
Landing Gear Retracting Strut
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_46-11-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-11-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C Subject: Landing Gear Retracting Strut Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: The Boeing Company Model: AT-6 (SNJ-2) | AT-6A (SNJ-3) | AT-6B | AT-6C (SNJ-4) | BC-1A 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: 46-11-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-11-01 SUBJECT HEADING: Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-11-01 NORTH AMERICAN: (Was Service Note 2 of AD-2-575-3.) Applies Only to Army BC-1A, AT-6, -6A, -6B, -6C; Serial Numbers Below 41-34249 and Navy SNJ-2, -3, -4; Serial Numbers Below 0-43692. Inspection required at each periodic inspection unless doubler angles are installed. Inspect the inboard end of the landing gear retracting strut attachment support channel, P/N 55-14102 or 66-14102-1, at the wing outer panel joint, for cracks. If cracks are found in any channel, it shall be reinforced as follows: A. For cracks less than 2 inches long, install 0.062 inch-29/32 inch x 1 inch x 6 3/4 inches long, SAE No. 4130 steel, cadmium-plated ( or 0.091 inch-24ST alclad) doubler angles in the upper corners of the inboard ends of each cracked channel. Drill a 1/8-inch stop hole at the end of each crack. Attach the 29/32-inch leg by picking up the existing rivet pattern through the wing skin and the channel upper flange. The rivets through the wing attach angle should be replaced with AN 3 bolts, or equivalent. Attach the 1-inch leg to the side of the channel using a row of seven AN 442-AD4 rivets or equivalent, at approximately 1 1/8-inch spacing. B. For cracks over 2 inches long, install 0.062 inch-29/32 inch x 1 3/8 inches x 6 3/4 inches long SAE No. 4130 steel, cadmium-plated, doubler angles in the upper corners of the inboard ends of each channel containing a crack over 2 inches long. Drill a 1/8-inch stop hole at the end of each crack. Attach 29/32-inch leg as described in paragraph A. Attach 1 3/8-inch leg to the side of the channel using two rows of seven AN 442-AD4 rivets, or equivalent, at approximately 1 3/8-inch spacing. C. For cases where no cracks are found, install the same doubler angles as required in paragraph A, except that they need not exceed 4 inches in length, or inspect at each periodic inspection. In order to permit installation of rivets with the wing outer panel installed on the airplane, approved type blind 5/32-inch rivets may be used in the 1-inch or the 1 3/8-inch leg of the doubler angle. (Supplement No. 1 to North American Service Bulletin dated March 6, 1946, covers this subject also.) FOOTER:
Document Text
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AD Final Rules - DRS_46-11-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-11-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C Subject: Landing Gear Retracting Strut Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: The Boeing Company Model: AT-6 (SNJ-2) | AT-6A (SNJ-3) | AT-6B | AT-6C (SNJ-4) | BC-1A 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: 46-11-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-11-01 SUBJECT HEADING: Airworthiness Directives; North American Models BC-1A, AT-6, AT-6A, AT-6B, and AT-6C ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-11-01 NORTH AMERICAN: (Was Service Note 2 of AD-2-575-3.) Applies Only to Army BC-1A, AT-6, -6A, -6B, -6C; Serial Numbers Below 41-34249 and Navy SNJ-2, -3, -4; Serial Numbers Below 0-43692. Inspection required at each periodic inspection unless doubler angles are installed. Inspect the inboard end of the landing gear retracting strut attachment support channel, P/N 55-14102 or 66-14102-1, at the wing outer panel joint, for cracks. If cracks are found in any channel, it shall be reinforced as follows: A. For cracks less than 2 inches long, install 0.062 inch-29/32 inch x 1 inch x 6 3/4 inches long, SAE No. 4130 steel, cadmium-plated ( or 0.091 inch-24ST alclad) doubler angles in the upper corners of the inboard ends of each cracked channel. Drill a 1/8-inch stop hole at the end of each crack. Attach the 29/32-inch leg by picking up the existing rivet pattern through the wing skin and the channel upper flange. The rivets through the wing attach angle should be replaced with AN 3 bolts, or equivalent. Attach the 1-inch leg to the side of the channel using a row of seven AN 442-AD4 rivets or equivalent, at approximately 1 1/8-inch spacing. B. For cracks over 2 inches long, install 0.062 inch-29/32 inch x 1 3/8 inches x 6 3/4 inches long SAE No. 4130 steel, cadmium-plated, doubler angles in the upper corners of the inboard ends of each channel containing a crack over 2 inches long. Drill a 1/8-inch stop hole at the end of each crack. Attach 29/32-inch leg as described in paragraph A. Attach 1 3/8-inch leg to the side of the channel using two rows of seven AN 442-AD4 rivets, or equivalent, at approximately 1 3/8-inch spacing. C. For cases where no cracks are found, install the same doubler angles as required in paragraph A, except that they need not exceed 4 inches in length, or inspect at each periodic inspection. In order to permit installation of rivets with the wing outer panel installed on the airplane, approved type blind 5/32-inch rivets may be used in the 1-inch or the 1 3/8-inch leg of the doubler angle. (Supplement No. 1 to North American Service Bulletin dated March 6, 1946, covers this subject also.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
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