46-39-04: Fuel Tank Selector and Crossfeed Valves
FAA order 46-39-04 is an airworthiness directive. The FAA's subject line: Fuel Tank Selector and Crossfeed Valves. It names Douglas C-54: about 7 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: fuel system.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- The Boeing Company
- Models
- C54-DC, C54A-DC, C54B-DC, C54D-DC, C54E-DC, C54G-DC
- On this site
- Douglas C-54 7 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 (575 characters)
46-39-04 DOUGLAS: (Was Mandatory Note 7 of AD-762-7.) Applies to C-54 Series Aircraft. \n\n\tTo be accomplished not later than November 15, 1946. \n\n\tInstances of valve freezing, due to ice forming in the detent chamber, have been reported on fuel tank selector and crossfeed valves. To prevent valve freezing, the Parker and Hydro Aire valves must be reworked by filling the detent chamber with Dow Corning compound No. 4 and installing a washer to retain the compound and to act as a water shield. \n\n\t(Douglas Drawings 4331597 and 2331524 cover this same subject.)
Related safety bulletins advice on the same designs, not orders
2014-11-24NM-15-03 · Flight Controls
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/46-39-04.json · aircraft systems.