MD-11 Eng #2

[adarob]

hey folks , can any one answer following questions about MD-11's # 2 Eng as illustrated in the pic bellow

http://www.gmrup.com/d3/up13285403621.jpg

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 or it sucks fuel by the fuel pump which is fitted on the Eng AGB ?



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 MD-11 ? i mean does it have manual OVRD handle too or no ? if yes , does it need to use the cherry pecker or taller ladder to do manual OVRD ?

[Flightmech]

1. The APU uses the #2 TANK aft pump for its fuel supply. There is also a APU START PUMP (DC) that is used for APU operation if AC power is not available (for example starting the APU off the battery)

2. Yes, the #2 engine has a manual start system which consists of a teleflex cable from the start valve to a handle in the tailcone compartment. You still need a stand or platform to access the handle though.

[adarob]

mr. flightmech , excellent D , now i know how we deliver fuel to the APU , but my question was about Eng # 2 , 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 or it sucks fuel by the fuel pump which is fitted on the Eng AGB ?

[Flightmech]

Sorry i misunderstood.

There are 3 AC pumps in the #2 TANK that supply fuel to the #2 engine under normal operation mounted on the rear spar or in underwing cavity. Fuel runs through a shrouded line that runs from the #2 tank through the left wheel well and along the LH sidewall of the aft lower cargo compartment then rearwards and upwards to the #2 engine. There is a circumstance where if a #2 FILL VALVE fault is detected the Fuel System Controller will shut-off the #2 TANK pumps to protect the fuel in the #2 TANK and turn on a TAIL TANK ALTN PUMP which feeds the #2 engine directly from the TAIL TANK. When this fuel is used and the airplane goes to tank-to-engine config it turns the TANK 2 PUMPS back on. Very clever!

This is of course the LP (low pressure) side of the system. The engine itself has a fuel pump (HP) and Hydromechanical Unit (HMU) that controls the fuel going into the fuel nozzles. These are driven by the gearbox on the engine itself.

The #2 ENGINE will not suction feed like 1 and 3. If you lose the boost pumps (TANK 2 and/or TAIL TANK ALTN depending on fuel load/config) the engine will flame out

[adarob]

mr. flightmech , really idk how to thank u for this useful N full answer , god bless u :O:O