55-17-01: Flap Torque Tube Bolts
FAA order 55-17-01 is an airworthiness directive. The FAA's subject line: Flap Torque Tube Bolts. System: flight controls.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Lockheed Aircraft Corporation
- Models
- 1049-54, 1049B-55 (Navy R7V-1), 1049C-55, 1049D-55, 1049E-55, 1049F-55 (USAF C-121C), 1049G-82, 149-46, 49-46, 649-79, 649A-79, 749-79, 749A-79
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 (980 characters)
55-17-01 LOCKHEED: Applies to All Models 49, 149, 649, 749, and 1049 Airplanes.
Compliance required by December 1, 1955, unless already accomplished.
A recent failure of wing flap torque tube assembly, P/N 326605-3, on a Model 1049C is attributed to a defective bolt, P/N AN 23-19. Initial overtorque of the bolt is suspected as the cause of failure of the bolt. It is therefore necessary that all Constellation and Super Constellation airplanes be inspected to ascertain proper installation of bolts, including bolt torque, on all wing flap torque tubes.
Proper torque value for the AN 23-19 bolts is 10 to 20 inch-pounds. Nut torque must be checked with a torque wrench and all overtorqued bolts replaced. If necessary, the next size longer bolt (P/N AN23-20) may be used to facilitate installation within proper torque tolerances. Washers may be used as required, but not to exceed two under the head or two under the nut, to prevent the nut from bottoming on the shank.
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 November 6, 2026. Connections as data: /graph/directive/55-17-01.json · aircraft systems.