Broke From United States of America, joined Apr 2002, 1325 posts, RR: 3
Reply 1, posted (12 years 7 months 2 weeks 5 days 15 hours ago) and read 3768 times:
The DC-8 had four fuel tanks in all versions and some had a fuel tank that included in both inboard leading edges and were plumbed together as one tank. The airplane had a fuel tank in the outboard section of each wing (different configuration for different models) and a fuel tank in the inboard section of each wing that usually extended into the center section that was under the cabin floor where the wing passed through the fuselage (again the exact configuration varied between models). If you were not careful, you drain a tank dry that you didn't want to or flameout an engine or engines.
You could transfer fuel between tanks and feed each engine from any tank. This system was a good example of using the principle of turning something "on" before turning something "off", i.e. boost pumps, fuel valves, crossfeed valves.
The tanks were fueled from a panel on the right wing lower surface trailing edge. When the external fueling panel was powered for fueling, the FE's fuel panel was not and the gauges there could read anything. A not uncommon oops on the DC-8.
JETSTAR From United States of America, joined May 2003, 1748 posts, RR: 9
Reply 2, posted (12 years 7 months 2 weeks 5 days 15 hours ago) and read 3771 times:
Federal Aviation Regulation design requirements for multi engine airplanes is that each engine must have its own dedicated fuel tank to be used for take off and landings.
As Broke described correctly the DC-8 has 4 main fuel tanks because it is a 4 engine airplane. All other additional tanks can be used after takeoff to provide fuel to the engines and are usually used until empty and then the main fuel tanks are selected for the remainder of the flight.
If there is fuel left in the additional or aux fuel tanks by the time the airplane starts its approach, the main fuel tanks must be selected until the aircraft is on the ground.