# AD 46-11-01: Landing Gear Retracting Strut - Type: Airworthiness directive - Status: Current - Products: Boeing AT-6 (SNJ-2), AT-6A (SNJ-3), AT-6B, AT-6C (SNJ-4) and BC-1A - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Registered aircraft: 107 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/52074CFB7320098D86256A4500682EAD.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/46-11-01 ## The airworthiness directive 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.) ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A-2-575](https://openairdocs.org/tcds/A-2-575): The Boeing Company; names 5 of 9 models: AT-6A (SNJ-3), BC-1A, AT-6C (SNJ-4), AT-6 (SNJ-2), AT-6B ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 107 (107 by airframe model, 0 by engine model) - Makers: North American 82, North American/Victoria MNT LT 20, North American / Crosser G 1, North American-Collins 1, North American/Case M V JR 1, North American/Levrett 1, North American/Walker/Screws 1 Models with the most aircraft: - [North American AT-6C](https://openairdocs.org/model/north-american-at-6c): 43 aircraft (airframe model) - [North American AT-6](https://openairdocs.org/model/north-american-at-6): 28 aircraft (airframe model) - [North American/Victoria MNT LT AT-6A](https://openairdocs.org/model/north-american-victoria-mnt-lt-at-6a): 20 aircraft (airframe model) - [North American AT-6A](https://openairdocs.org/model/north-american-at-6a): 5 aircraft (airframe model) - [North American AT-6B](https://openairdocs.org/model/north-american-at-6b): 3 aircraft (airframe model) - [North American AT-6C(SNJ-4)](https://openairdocs.org/model/north-american-at-6c-snj-4): 3 aircraft (airframe model) - [North American-Collins AT-6A](https://openairdocs.org/model/north-american-collins-at-6a): 1 aircraft (airframe model) - [North American/Walker/Screws AT6C](https://openairdocs.org/model/north-american-walker-screws-at6c): 1 aircraft (airframe model) - [North American / Crosser G AT6A](https://openairdocs.org/model/north-american-crosser-g-at6a): 1 aircraft (airframe model) - [North American/Levrett AT6-C](https://openairdocs.org/model/north-american-levrett-at6-c): 1 aircraft (airframe model) - [North American/Case M V JR AT-6](https://openairdocs.org/model/north-american-case-m-v-jr-at-6): 1 aircraft (airframe model) All 12 models: https://openairdocs.org/ad/46-11-01/models.md Every aircraft: https://openairdocs.org/ad/46-11-01/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.