no need for standby power for starting the apu

Bus transfer switch should be on too.

I don't think it will start if your battery power is too low also, but in that case it will indicate "Fault" if it fails to start.Yesterday I started the APU on battery power, went to set fuel in the CDU and accidently put 15 rather than 15000kg and the APU cut out due to lack of fuel. I corrected the fuel issue only to find the APU wouldn't start again. I connected ground power and tried again, wouldn't start, I started engines on air start and tried again... wouldn't start. Checked the failures page and it had failed. I think it failed due to all the start attempts in short succession, like happened to me when I attempted to start it a few times at various altitutes (slightly past published limits). Cancelled that flight cause the MEL pointed out I had to have it functioning for the ETOPS flight I was about to attempt. :)

haha such a long topic on how to start the APU. Think about it..

I tried to start it without any fuel and fried it. Even with clearing all faults through the maintaince screens I could not get it to work again without having to reload a clean aircraft. Very realistic indeed! Haven't made that mistake again.

And if you're really are bored:

A DC operated APU fuel boost pump is installed to ensure positive fuel pressure to the APU fuel control unit. During APU start and operation, the pump operates automatically when the APU fuel control unit senses low fuel pressure. The pump shuts off automatically when an AC fuel pump pressurizes the fuel manifold. If the AC and DC fuel pumps are not operating, fuel is suction fed from the No. 1 tank.

This only optional equipment and I don't think it's very common.

or you could download these flow checklists and go through it step by step the easy way. http://library.avsim...ftp&DLID=161004 Use the 800 Model with HINTS.

A fuel pump on is not actually required to start or run the APU in the real plane. For the first four or five years we had 737s we didn't turn the fuel pumps on. Later we changed the procedure to turn a pump on to reduce stress on the ECU.

How about to recap? For myself and other captains. :)1. the APU can start and operate in a "stand alone mode", in other words fuel is suction fed from main tank nr.1, then a DC fuel boost pump ensures a positive pressure allowing APU operations (see page 12.20.2 of FCOM v2 "APU FUEL FEED")2. (basing what said before) you can leave all AC fuel pump switches OFF, aircraft APU will start & operate without them.3. To prevent:

a.

fuel imbalances

(cause main tank nr. 1 will have less fuel than nr.2) and

b. failure of the DC fuel boost pump (probably not simulated?)

it is suggested to run APU switching ON the AC center fuel pump nr. 1.Is it all right?Thanks bye.

How about to recap? For myself and other captains. :)1. the APU can start and operate in a "stand alone mode", in other words fuel is suction fed from main tank nr.1, then a DC fuel boost pump ensures a positive pressure allowing APU operations (see page 12.20.2 of FCOM v2 "APU FUEL FEED")2. (basing what said before) you can leave all AC fuel pump switches OFF, aircraft APU will start & operate without them.3. To prevent:

a.

fuel imbalances

(cause main tank nr. 1 will have less fuel than nr.2) and

b. failure of the DC fuel boost pump (probably not simulated?) it is suggested to run APU switching ON the AC center fuel pump nr. 1.Is it all right?Thanks bye.

Boeing recommend switching the centre fuel pump 1 on so that you don't cause a fuel imbalance.Otherwise the fuel is taken from the left wing by default with no pumps on. Fred.

Does it come with a crank handle too?

Boeing recommend switching the centre fuel pump 1 on so that you don't cause a fuel imbalance.Otherwise the fuel is taken from the left wing by default with no pumps on.Fred.[/indent]

?Yes, the main tank nr.1 is just the tank in left wing. Bye.

Can you speed up the APU starting guys !!! The passengers are getting restless,

Can you speed up the APU starting guys !!! The passengers are getting restless,

It is quite slow indeed, but probably simulated as in real life. So I prefer that.Bye.

Thank you guyes for your help. Got the APU running now. I think the Problem is, when you turn on and off many switches, especially the bus-switches, something seems to run out of normal. When I reload a complete new flight and proceed the startup procedure from a fresh loaded cold&dark cockpit everything works well and the apu starts with the first try. If you only reload the panel-state --> strange, sometimes working, sometimes not.