49-23-01: Fuselage Truss
FAA order 49-23-01 is an airworthiness directive. The FAA's subject line: Fuselage Truss. It names Boeing 75, Boeing A75 Stearman Kaydet, Boeing B75 Stearman Kaydet, Boeing D75, Boeing E75 Stearman Kaydet, Boeing IB75: about 1,644 aircraft on the U.S. register today across them, though an order usually covers particular versions or serial numbers rather than every one. System: airframe structure.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Boeing Airplane Company, Wichita Division
- Models
- 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), IB75A
- On this site
- Boeing 75 18 registered
Boeing A75 Stearman Kaydet 979 registered
Boeing B75 Stearman Kaydet 257 registered
Boeing D75 35 registered
Boeing E75 Stearman Kaydet 343 registered
Boeing IB75 12 registered
Dates and paperwork
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (1,186 characters)
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.
Related safety bulletins advice on the same designs, not orders
2017-10-10SW-17-28 · Fuel Quantity Indicator
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 5, 2026. Connections as data: /graph/directive/49-23-01.json · aircraft systems.