47-27-04: Exhaust Collector Rings
FAA order 47-27-04 is an airworthiness directive. The FAA's subject line: Exhaust Collector Rings. 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: engine.
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, DC-4
- 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 (1,003 characters)
47-27-04 DOUGLAS: (Was Mandatory Note 18 of AD-762-7.) Applies to All C-54 and DC-4 Series Airplanes Having Exhaust Collector Rings Made Up of Top Segments P/N 5174842-56 L.H. and 5174529-56 R.H. \n\n\tTo be accomplished not later than the first engine change subsequent to July 15, 1947, but in any event not later than October 15, 1947. \n\n\tSeveral reports have been received of cracking failure of the collector ring "Y" outlet assembly due to breathing of the exhaust stack. This induces failure which creates a fire hazard. This type of exhaust collector "Y" is not reinforced with a flange and is shown on page 4, Douglas Service Bulletin No. DC-4 No. 31. To correct this condition weld a scalloped stiffener flange on the exhaust collector aft of the "Y" outlet assembly. \n\n\t(Douglas Service Bulletin No. DC-4 No. 68 covers this same subject.) \n\n\tUntil this repair is accomplished, inspection for cracks should be made immediately and at periods not to exceed 50 hours of operation.
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/47-27-04.json · aircraft systems.