Oli
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Engine Start With The 747/200

Sat Jan 09, 2010 10:46 pm

Hi,

I am using a great simulation of the 747/200 (Ready for Pushback) and it is stated that, for engine start, the fuel panel must be configured so that wing tank 2 feeds all engines.
This is then modified for takeoff.

Is that the real procedure and, if so, why?

Thanks in advance for your input,

Olivier
 
lowrider
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RE: Engine Start With The 747/200

Sun Jan 10, 2010 1:01 am

If I recall correctly, the configuration for engine start is Tank to Engine. There are 6 or 8 tanks in the wings, depending on the configuration purchased, 4 main, and 2 (or 4) reserve tanks. For engine start each main tank feeds its respective engine. Why? The simple answer is Boeing wanted it that way. But it also verifies the operation of the pumps in each main tank, something that would not be done if the engines were started in an Inboards to All, Center to all, or Center to Outboard feed configuration. For take off you may use Center to Outboard, or Tank to Engine, depending on your fuel load.
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747classic
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RE: Engine Start With The 747/200

Sun Jan 10, 2010 2:52 pm

With only wing tanks containing fuel, the engine start is accomplished with (main)tank to engine.
Fuel panel configuration : All main tank boost pumps on and X-feed vlv's 1 & 4 open and 2 & 3 closed.

With wing tanks full and when center wing tank also contains fuel (more than 1800 kgs) the start is made with engines 1 & 4 fed by center wing tank, with both CW override jettison pumps selected on and overriding the main tank 1 &4 boostpumps.
Fuel panel configuration : All main tank boost pumps on, both CW overr/jett pumps on, X-feed vlv's 1 &4 open and 2 & 3 closed.

Ref : 747 OM part B ,normal procedures, 6.2.2.11.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
lowrider
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RE: Engine Start With The 747/200

Sun Jan 10, 2010 7:16 pm



Quoting 747classic (Reply 2):
With wing tanks full and when center wing tank also contains fuel (more than 1800 kgs) the start is made with engines 1 & 4 fed by center wing tank,

Thanks. I couldn't remember if that feed was used for starting or not.
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RE: Engine Start With The 747/200

Sun Jan 10, 2010 8:13 pm

Quoting Oli (Thread starter):
the fuel panel must be configured so that wing tank 2 feeds all engines.

Maybe you are confused with the following.
During ground operations : With all main tank boost pumps selected off, auto fuel feed to the APU is accomplished with the aft boost pump of main tank #2.

[Edited 2010-01-10 12:14:31]
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
Oli
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Posts: 25
Joined: Mon Jun 20, 2005 5:43 pm

RE: Engine Start With The 747/200

Sun Jan 10, 2010 8:43 pm

Hi,

Thanks you all for your input - I read the manual again and I think they made a mistake - a tank to engine configuration makes more sense (this is what is used for takeoff as well if I am not mistaken - if the center tank is full, then the setting "main center tank feeds all engines" must be selected during the climb, until the main center tanks is empty, am I correct?).

Happy flying,

Olivier
 
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RE: Engine Start With The 747/200

Mon Jan 11, 2010 6:32 am

If the centerwing tank contains fuel, you have to select "Center wing tank to all engines" during CLB.
Fuel panel configuration :
All X-feed valves open, 1 & 4 boostpumps off, 2 & 3 boostpumps on, CW overr/jett pumps on.

If center wing is empty (CW overr/press lights flashing) :
All X-feed valves open, 1 & 4 boostpumps off, 2 & 3 boostpumps on, CW overr/jett pumps off.
Scavage pump on : to get remaining fuel out of centerwing tank into to main tank #2.
Now you are on : main tank 2 & 3 feeding all engines.
Operating a twin over the ocean, you're always one engine failure from a total emergency.

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