APU won't start

[Able Dog]

I hope I am doing this right. I started leaning A-10C several years ago and felt I was pretty successful. I took some time off and wanted to start playing it again. However, now when I do the start-up, the APU doesn't start. Specifically, after switching it on, the RPMs only reach about 60% and I don't hear the usual sound of it running. Has my program gotten corrupted?  Any ideas on how to fix this? Thanks in advance.

[Scotch75]

I hope I am doing this right. I started leaning A-10C several years ago and felt I was pretty successful. I took some time off and wanted to start playing it again. However, now when I do the start-up, the APU doesn't start. Specifically, after switching it on, the RPMs only reach about 60% and I don't hear the usual sound of it running. Has my program gotten corrupted?  Any ideas on how to fix this? Thanks in advance.

Have you switched on the battery and inverter? Also, check fuel switches are correct.
Cheers!


Sent from my SM-G998B using Tapatalk

[Yurgon]

4 hours ago, Able Dog said:

Specifically, after switching it on, the RPMs only reach about 60% and I don't hear the usual sound of it running. Has my program gotten corrupted?  Any ideas on how to fix this?

There's not a whole lot that one could do wrong. As Scotch75 says, Battery + Inverter + APU START and that should be it.

The fuel boost pumps could even be switched off, the APU should be able to start without them. And (to my surprise, I must admit) I could even get the APU started with Battery alone, didn't even need the Inverter.

Trying to start any of the engines before the APU is stabilized at 100% RPM is going to be a problem - can you confirm both throttles are in the OFF position, both ENG OPER switches are in NORM, and that the ENG START CYCLE indication is NOT showing on the Caution Light Panel?

The 101 of bugfixing:

• Remove any and all mods that you may have installed
• Run a full repair from the DCS Launcher
• If that still doesn't fix it, rename your Saved Games\DCS folder and try with a completely fresh config

A short track of the issue is also always a big help so we can check if we see the same issue and if there's something wrong. Maybe if the OAT is extremely high or low the APU doesn't start properly or so? A track could give immediate pointers here.

Edited 20 hours ago by Yurgon

[Czar]

4 hours ago, Able Dog said:

I started leaning A-10C several years ago and felt I was pretty successful. I took some time off and wanted to start playing it again.

Several years ago + feeling instead of knowing for sure through many trials is not good enough. (I've been there many times)

Approach it from the ground up. It can be a simple switch not found in other modules/aircraft that's by default off like the pesky A-10C APU GEN switch.
The APU might be running, sound queues are not good enough as you said you took some time off, and the APU Gen is off giving you only cockpit partial power and a bad diagnosis.

To add on what others helpful people pointed out above:
Go with a start up checklist, un-modded Warthog, check the right front lower panel especially the APU Gen switch.

Fair skies.

[Ivandrov]

From what I remember, attempting to turn on the APU gen before the APU reaches 100% stalls the APU start-up. 

[Yurgon]

9 hours ago, Czar66 said:

The APU might be running [...]

OP very clearly said the APU RPM doesn't go above 60%.

8 hours ago, Ivandrov said:

From what I remember, attempting to turn on the APU gen before the APU reaches 100% stalls the APU start-up. 

In the Caucasus Cold Start mission, that's not the case. I could switch on most consumers (IFFCC, radios, countermeasures, EGI+CDU, and a few more), switch on APU Gen, and then Battery + Inverter + APU Start, and it would start just fine and all electric consumers would come alive as the APU reaches 100% RPM.

Just to be clear, we shouldn't be doing this (I distinctly recall a SME saying "You don't start the APU loaded"), but it doesn't explain OP's observation.

[Czar]

45 minutes ago, Yurgon said:

OP very clearly said the APU RPM doesn't go above 60%.

I went for accuracy by volume of "fire".

The chances of OP also having a confusion on the gauges are high given how cluttered the front panel is and the APU EGT gauge which usually hovers at the 6 marker on startup of an engine is right next to the actual APU RPM gauge with the name 'APU' a bit covered at certain angles.

1. Is hard to fumble the apu start.
2. Is easy to forget the APU gen switch as no other module (american) has that need to turn on the APU gen.

I took my chances.

As an addition. The Warthog without fuel while attempting to turn on the APU will feature the RPM stuck at 30%:

 

Edited 9 hours ago by Czar66

[Czar]

11 hours ago, Yurgon said:

Trying to start any of the engines before the APU is stabilized at 100% RPM is going to be a problem - can you confirm both throttles are in the OFF position, both ENG OPER switches are in NORM, and that the ENG START CYCLE indication is NOT showing on the Caution Light Panel?

You're spot on on this. I believe you've found the issue.

APU RPM% gets stuck at 60% if any engine is out of the fuel cut off position or idle before the APU is fully started. (not a bug)

 

 

Edited 8 hours ago by Czar66