APU wont stop after engines start

[Joakkino 0]

Hello everyone!

 

I read that some users can't start up their APU. I have the exact opposite problem: when the engines of my (pmdg) 747 are running, i switch the APU selector to OFF but EICAS still say me "apu runnig" and if i turn the APU to on skipping the start step, generators power is avaiable.

Only one time i was able to turn it off (luckily): i simply made the switch become crazy, turning it in all 3 positions (off, on, start). But i know that this isn't the right way.

How can i solve it?

 

Thanks

Regards

 

ps. i edited the config file, so the apu burns fuel from my tanks and, as you can understand, i absolutely don't want keep apu running in flight (besides the fact that it would be useless).

[bowingic 7]

Hi

I don't fly the 747 but on the 767 (I use the LevelD) the APU is subjected to a one minute cool down period if the APU bleed valve is in use when the APU is shut down. When the APU is turned off the bleed valve cycles closed and the APU continues to run for one minute before shutting down.

Suspect it would be the same on the 747 and assuming that PMDG have modelled it.

 

[Joakkino 0]

I don't know... But i'm sure that, before posting here, i turn my engines on (in simple terms), taxi to the runway (in the opposite side of the airport), lift off, flown across first 4-6 waypoints and the APU was still running. So have passed several minutes, no?

 

Solution. Maybe...

Yesterday night, i think i've found a solution for the problem: while taxing to the runway, i switched the battery off (apu selector in off position) and then turned back on; i tried to move apu in ON position (skipping start) and the apu was no longer running.

I don't know if this is abnormal or not, but for me it worked. At least this time.

If this isn't the right solution, plaese do not hesitate to explain your solutions.

Thanks

Regards

[Eric_Parker 4]

After turning the APU selector to "Off" it takes appoximately 2 minutes for the device to shut down. If you monitor the overhead panel while operating the switch you will see that "Power Avail" lights go out immediately. But if you also monitor the EICAS subpanel for the "Stats" function, the APU readings remain constant during this period. The warning light on the master EICAS remains illuminated until the the APU actually begins to diminish.

 

I have had this airplane for a couple of years now and it has a steep learning curve.