Starting APU without any ground connection

[Schullebernd 0]

Hey pilots,After trying this more than 4 houres yesterday i decided to Ask you Professionals.The Problem is, i load the NGX with panelstate cold&dark. Turm on the Main and standby Battery Switch. After this i try to Start the APU but it doesn't work.I followed the electrical Startup Procedere with no Ground Power steps. Also tried the batteryStart. But i can't find an advice how to Start the APU and what are the conditions to successfully do this.Can anybody help me please.Thanks a LotMarcel

[Will069 0]

Did you turn on the fuel switches?

[KLM_777_300ER 0]

Fuel switch!!!!!! Your Apu is a small turbine engine and needs fuel.

[Fabri91 0]

Might be an obvious suggestion, but the APU switch needs to be put in the START position, after which it will spring back to the ON position.

[ajacied551 1]

Did you push the APU START switch to START, This switch has three position's OFF, ON and START, When position the switch to ON you must continue to go to the START position, when you release the switch then the switch jumps back to ON . During the Start sequence of the APU you see the LOW OIL PRESSURE light lit up momentarely. P.S The Fuel pumps don't run on battery power only, you need to supply 115 AC power, to do that you start the APU or connect the external power source, The APU suchs fuel from Main tank #1 that is regulated by the APU Fuel control unit, so it's not necessary to switch ON the fuel pump'sWhen the APU has started it better to switch ON the Main #1 AFT Fuel BOOST pump for a better performance of the APU.

[Rieder 3]

Once you met all the above points and pressed the APU starter switch, got the low oil pressure light you need to wait a little while. Watch the EGT and it will go up maybe 8/9 then drop a lot lower. Shortly after the APU light will come on, switch the APU Gens on and you`re good to go. Don`t forget, once all checks are done you need to push back before engine starting and fetching the engine generators online. Thats the way I do it anyway, right or wrong.

[Chrjs 61]

Did you push the APU START switch to START, This switch has three position's OFF, ON and START, When position the switch to ON you must continue to go to the START position, when you release the switch then the switch jumps back to ON . During the Start sequence of the APU you see the LOW OIL PRESSURE light lit up momentarely. P.S The Fuel pumps don't run on battery power only, you need to supply 115 AC power, to do that you start the APU or connect the external power source, The APU suchs fuel from Main tank #1 that is regulated by the APU Fuel control unit, so it's not necessary to switch ON the fuel pump'sWhen the APU has started it better to switch ON the Main #1 AFT Fuel BOOST pump for a better performance of the APU.

That's right, no need to turn the fuel pumps on for APU operation. one addition, i f you have fuel in the center tank you should turn on the Center Fuel Pump 1 so that the APU takes fuel from the center tank and you won't run into a fuel imbalance.... regards, christopher volle

[flyingscampi 2]

Check the procedure SP 6.1 in FCOM 1, maybe one of your switches is in the wrong position.

[MarcM 0]

Have you checked your Standby Power ? Just below your Battery switch !

[qantas747 4]

APU bleed might fix it???

[RYR738 9]

APU bleed might fix it???

The APU doesn't need bleed air to start ! It can however provide bleed air after it has started. Fred.

[Houghton11 12]

I think he means make sure the APU bleed valve is closed or APU Bleed off on the air panel up there.

[ZachLW 37]

I've yet to see anyone mention the fact that it could have broken. Maybe check your failures. I see lots of answers that don't have an ounce of truth, too!

[Lusche 3]

APU operation requires the following: •APU fire switch on the overheat/fire panel must be IN•APU fire control handle on the APU ground control panel must be IN•battery switch must be ON.

[derianc 0]

^ Yeah, and make sure both Battery AND standby covers are closed (this will automatically set them to the on position).