Using APU after long flight

[teofilo 11]

Hey guys,

I am no expert in the 747 so I have a question.

After a long flight, I found out I cannot turn on the APU, I guess fuel on the tank it uses goes empty during flight.

How can I send fuel to that tank so that there is something to start the APU on after landing?

Tried looking on the manual but nothing so far.

 

Thanks much in advance.

 

Teo

[scandinavian13 5,192]

 

 

How can I send fuel to that tank so that there is something to start the APU on after landing?

 

The best way to do this is to ensure that the tank has fuel to begin with. At some point during the flight, the EICAS will show FUEL TANK/ENG. This means that you should turn off the fuel override pumps, and turn off the crossfeeds between the inner and outer engines (these switches will be unguarded, unlike the other crossfeeds, which are guarded with a plastic cover).

[teofilo 11]

Excelent tip, thanks a lot!

[pcubine 143]

 

 

the EICAS will show FUEL TANK/ENG.

Is there anything worse than no APU fuel that might happen if the message is disregarded?

[scandinavian13 5,192]

Is there anything worse than no APU fuel that might happen if the message is disregarded?

 

It's been so long since I've flown the 777 that when I get the 744 in my hands. I'm unsure enough in my potential answer that I'll disclaim it with "I haven't flown this plane since my FS9 days." That was 2008, by the way...

 

...but...

 

Because the inner tanks can hold more than the outer tanks, the 744 has OVERRIDE pumps, which throw out enough fuel to run all four tanks off of the inner tanks. What this means is that if you leave them on past the "even" point (where all inner and outer tanks are equal), the OVERRIDE pumps will continue to throw heaps of fuel out of the inner tanks, which will run them dry. Fuel will continue to feed from the outer tanks, but those don't have O-pumps, so you're running four engines off of the outer tanks that don't have the extra pumps to toss all that fuel out. It'll work, but I wouldn't call it ideal.

 

As you can see by the end result of post 1, one of the potential issues with leaving the O-pumps on is that the APU won't be able to pull fuel from the inner left (I think that's the tank it pulls from - all from six year old memory at this point - where's Qavion when you need him?). Others are potential fuel starvation of the engines due to inadequate pressure (though I'd say most normal ops you'd be okay for the most part). Having all of that weight at the outer part of the wings would end up causing a lot of stress to the outer portions, too, though the stress fractures caused over time aren't likely something you'll find in the sim. That's all I can think of at the moment.

 

...oh, and the group facepalm that you'll face when posting about it.

 

Judging by how many "bug" reports that got posted about the PILOT RESPONSE "error," I'm guessing we'll have quite a few that either read "FUEL TANK/ENG bug" or "744 outer pumps not working" / "744 draining inner tanks improperly" / variations.

 

[i'm hoping RSR doesn't read that and shudder...Not looking forward to stepping into the office...again.  ]

[pcubine 143]

Others are potential fuel starvation of the engines due to inadequate pressure (though I'd say most normal ops you'd be okay for the most part).

Thanks for the information. The only show stopper looks like fuel starvation that is only potential. However, on second thought this morning I don't want to get in the habit of ignoring warning message that I believe don't have any serious consequences. Plus I have forgotten how to fly this plane. I think I will wait on version 2 and relearn to fly it using tutorial 1.