adarob

hey folks , i ve some questions in regard with a/c's that have 3 eng's such as : md11, dc10, L1011, 727 etc... & specially on Eng # 2 which is fitted in the tail

1- how we deliver fuel from fuel tanks to Eng # 2 , is it like the APU has a fuel pump fitted in the rear spar of CTR fuel tank to feed the APU ?



2- during Eng start , for example on A320 , in case of start valve not opened automatically , we open it manually from the manual OVRD handle , the question is how we do that on Eng # 2 on tri star a/c's ? i mean does it have manual OVRD handle too or no ? if yes , does it need to use the cherry pecker to do manual OVRD ?

MarkerInbound

On the 727 it is the same as the other engines, fuel lines run from the tanks to the engines. Crossfeeds allow any tank to supply fuel to any engine. Boeing says the engine driven low pressure pump should suction feed up to ~25,000, the electric boost pumps would be required above that point. On most 727s the apu does not require an in tank boost pump since it sits level with the center tank.

Doing a manual start just takes a taller ladder.

JammedStab

Seem to remember that the engines on the 727 are all the same height above the ground. Does the ladder really need to be taller?

Exaviator

You are quite correct J.S. the center engine intake duct (S Duct) is higher, but the engines are at the same level

adarob

mr. MarkerInbound , good answer , thnx alot dude

MarkerInbound

See what happens when you haven't flown the airplane for 5 years. And I was always up front making funny hand signals out the window to one mechanic who relayed them to the second mechanic standing on the ladder.