47-51-12: Carburetor Airscoop
FAA order 47-51-12 is an airworthiness directive. The FAA's subject line: Carburetor Airscoop. It names Douglas DC-3: about 155 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: engine.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- The Boeing Company
- Models
- DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G
- On this site
- Douglas DC-3 155 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 (743 characters)
47-51-12 DOUGLAS: Applies to All converted C-47 Series Aircraft With Ram Non-ram (Hydraulic) Type Carburetor Airscoop. \n\nTo be accomplished not later than March 1, 1948. \n\nCompliance with the following items is necessary to preclude carburetor icing: \n\n1.\tThe carburetor alcohol system must be used. \n\n2.\tThe accessory cowling and engine fire seal must maintain not more than 1/4-inch clearance of the collector ring. \n\n3.\tThe cable system for operation of the hot air door must be rigged to 30 pounds tension. \n\n(Part B of Douglas Service Bulletin DC-3 No. 251 dated April 15, 1947, covers this same subject. Part A of the same Bulletin is not mandatory, but optional compliance may be accomplished when parts are available.)
Related safety bulletins advice on the same designs, not orders
2014-11-24NM-15-03 · Flight Controls
2008-06-12NM-08-28 · Landing Gear: DC-3 Tail Wheel Fork Check
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/47-51-12.json · aircraft systems.