# AD 49-23-01: Fuselage Truss - Type: Airworthiness directive - Status: Current - Products: Boeing Airplane Company, Wichita Division 75 (Army PT-13), A75 (Army PT-13A, -13B, -13C), A75J1 (Army PT-18), A75L3, A75L300, A75N1 (Army PT-17, -17A, Navy N2S-1, -4), B75 (Navy N2S-5), B75N1 (Navy N2S-3), D75N1 (Army PT-27), E75 (Army PT-13D, Navy N2S-5, PT-13D/N2S-5), E75N1 (Army PT-13D, Navy N2S-5, PT-13D/N2S-5) and IB75A - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Registered aircraft: 1,654 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DD8D30A04D35CD5F86256A34005BB0B3.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/49-23-01 ## The airworthiness directive 49-23-01 BOEING: Applies to All Model 75 Series Airplanes With Crop Dusting or Seeding Hopper Installations. Compliance required prior to next periodic inspection. Inspect to determine whether fuselage bottom truss was altered for installation of hopper throat. All alterations involving the removal or revision of the truss members require that equivalent structural strength be provided. One open bay in the bottom truss either immediately forward or immediately aft of the cross member (streamline tube) at Station 2L is permissible provided that it is limited to a rectangle bounded by the longerons, the above-mentioned cross member and a 7/8 x 0.035, or larger, x4130 tube parallel to the streamline tube and not more than 8 inches forward or aft thereof. The inside corners of this open rectangle should have 0.065-inch x 4130 gussets, or equivalent, extending along the longerons at least 2 inches. (Boeing Report No. WD-10645 covers this same subject and includes an alternate alteration recommended as preferable to the above. Copies of the report are obtainable from the Boeing Airplane Co., Wichita Division, Wichita 1, Kansas.) This supersedes AD 46-31-03. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A-743](https://openairdocs.org/tcds/A-743): The Boeing Company; names 12 of 12 models: B75N1 (Navy N2S-3), 75 (Army PT-13), A75J1 (Army PT-18), E75 (Army PT-13D; Navy N2S-5; PT-13D/N2S-5), A75L3, E75N1 (Army PT-13D; Navy N2S-5; PT-13D/N2S-5), A75L300, A75 (Army PT-13A; -13B; -13C)… ## 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: 1,654 (1,654 by airframe model, 0 by engine model) - Makers: Boeing 1,642, Boeing Stearman/Huff 1, Boeing/Cains Richard G 1, Boeing/Dekker 1, Boeing/Hawk 1, Boeing/Humm Stanley 1, Boeing/Johnson 1, Boeing/Mays 1, Boeing/Mehrer 1, Boeing/Mountain View Air Rep 1 Models with the most aircraft: - [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17): 759 aircraft (airframe model) - [Boeing E75](https://openairdocs.org/model/boeing-e75): 261 aircraft (airframe model) - [Boeing B75N1](https://openairdocs.org/model/boeing-b75n1): 241 aircraft (airframe model) - [Boeing A75](https://openairdocs.org/model/boeing-a75): 93 aircraft (airframe model) - [Boeing E75N1](https://openairdocs.org/model/boeing-e75n1): 79 aircraft (airframe model) - [Boeing A75N1](https://openairdocs.org/model/boeing-a75n1): 59 aircraft (airframe model) - [Boeing D75N1](https://openairdocs.org/model/boeing-d75n1): 35 aircraft (airframe model) - [Boeing A75L300](https://openairdocs.org/model/boeing-a75l300): 33 aircraft (airframe model) - [Boeing A75L3](https://openairdocs.org/model/boeing-a75l3): 32 aircraft (airframe model) - [Boeing 75](https://openairdocs.org/model/boeing-75): 18 aircraft (airframe model) - [Boeing B75](https://openairdocs.org/model/boeing-b75): 15 aircraft (airframe model) - [Boeing IB75A](https://openairdocs.org/model/boeing-ib75a): 12 aircraft (airframe model) - [Boeing E75(N2S-5)](https://openairdocs.org/model/boeing-e75-n2s-5): 2 aircraft (airframe model) - [Boeing A75J1](https://openairdocs.org/model/boeing-a75j1): 2 aircraft (airframe model) - [Boeing/Smith A75N1](https://openairdocs.org/model/boeing-smith-a75n1): 1 aircraft (airframe model) - [Boeing/Dekker A75N1](https://openairdocs.org/model/boeing-dekker-a75n1): 1 aircraft (airframe model) - [Boeing Stearman/Huff A75-N1](https://openairdocs.org/model/boeing-stearman-huff-a75-n1): 1 aircraft (airframe model) - [Boeing/Mays A75N1](https://openairdocs.org/model/boeing-mays-a75n1): 1 aircraft (airframe model) - [Boeing/Hawk E-75](https://openairdocs.org/model/boeing-hawk-e-75): 1 aircraft (airframe model) - [Boeing/Porter/Epperson B-75N1](https://openairdocs.org/model/boeing-porter-epperson-b-75n1): 1 aircraft (airframe model) All 27 models: https://openairdocs.org/ad/49-23-01/models.md Every aircraft: https://openairdocs.org/ad/49-23-01/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.