Asobo A310 APU doesn't want to start in the Flight Deck Preparation checklist

User Support Hub Aircraft & Systems
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1

Hello,

I’ve been having a total blast with FBW A320NX. I wanted to try a slightly more challenging plane, and that’s when A310 got released.
Everytime i want to learn a new plane, i start in COLD&DARK mode and while going through the MSFS checklists, i also create sort of a “cheatsheet” in excel, it’s basically just a checklist, but condensed to the most essential stuff. I’m leaving out the various system checks that always have the correct values by default anyway etc.

So, i’m creating the A310 cheatsheet, going through the official MSFS checklist, eventually getting to the APU (Start) part.
There are actually TWO APU Start phases.
One is in the Preliminary Cockpit Preparation checklist - it says “APU (as required)”.
Since i never flown this plane, and i’m just learning to boot it up at this point, i always started the APU at this point, and it always started up without issues.
Then i continue further down, eventually getting to the second APU START phase, this time in the Flight Deck Preparation checklist.

The APU Start phase is right between “Cockpit Door closed” and “External Power OFF” lines.
The problem is, that since i started the APU earlier during the Preliminary Cockpit Prep, it should be already running at this point but for some reason it isn’t.

It looks as if at some point during the cockpit preparation the APU just stopped running without me noticing, and can’t be switched back on again. If i hit the start switch, the ON just flashes in the tooltip, then goes back to off.
Even the ECAM APU screen shows that it’s off.

So, i can’t continue with the boot up, because if i disconnect GPU with APU dead, the plane obviously goes dark and i gotta start from scratch.

The only idea i had to get around this problem is to NOT start the APU during the Preliminary Cockpit Prep. To start the APU later, during the Flight Deck Preparation phase, because if it starts then, i should be able to disconnect the GPU and continue with the checklist.

Any tips? Because i’m kinda lost here.
Is the APU supposed to run only for a few minutes and then goes off automatically?
Why can’t i start the APU again?

Thanks!

2

Have you switched on the left inner fuel pump?

3

Sorry for the delay, i couldn’t get to this server for some reason. The only thing i’ve seen was “Oops, there was a problem”.
What do you mean by inner left pump?
There is a lot of various pump buttons under FUEL section of overhead panel, and those are getting switched on, yes.

4

possibly a conflicted binding , are you using a yoke with buttons assigned or clicking using mouse?

5

Mapped to HOTAS buttons: Manual Brake, Parking Brake, AP, TRIM UP/DOWN, GEAR UP/DOWN, Reset camera to cockpit, Switch External/Internal camera (basically what END key does), Flaps UP/DOWN.
That’s about it i think.
For everything else i just have to click on the virtual switches & buttons in the cockpit, using mouse or VR controllers.
Btw, i found out that if i completely ignore the APU lines in the Preliminary Cockpit Preparation and start the APU at the end of the Flight Deck Prep, it does start, but ONLY if i switch on the button to the right of the APU Master SW (Fuel Pump) as well. Is there a chance you meant THAT fuel pump? Because earlier you wrote LEFT pump.
But if i start the APU during the Preliminary Cockpit Prep, it’s switched off by the time i get to the point where i should disconnect the external Power.
But i made two flights since i started the post, so the most probable explanation is that i somehow messed up.
Still, shouldn’t the APU start even without the Fuel Pump? Because when i push the button, the button says "OVERRIDE and ECAM APU page says “ACCELERATED”, which leads me to believe that this isn’t the standard APU start.

6

I use the expanded checklist with explanations in the inibulds A310 manual , its list has the inner pump as being used for apu start/run.

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Thanks for the screenshot! Dunno if that helps, i know that the INNER TK PUMP 2 was definitely ON, when i was switching the APU during Flight Deck Prep Checklist. It wasn’t on during the preliminary cockpit prep though.
The ACCEL Light only illuminates if i use the APU Fuel Pump - but the APU Fuel Pump (the button right of the APU Master Switch) isn’t actually mentioned in the checklist. I just tried it randomly out of sheer frustration, and it helped.
Although i eventually somehow forced the APU to start, i still have no idea why it didn’t work during my first two attempts to start the plane. Hmm…
I’m gonna keep this post alive for a bit.
Maybe i’m gonna find out what caused it later. Sometimes it happens.

1 Like
8

Ok, so - i was clearing up some OBS-recorded MSFS videos, and found out short videos that i recorded and forgot about.
Including two short videos i recorded, trying to document issue i’m describing in the post.
The problem wasn’t actually a problem. Just my oversight, and/or possible bug on inibuilds/Asobo’s part.
Turns out that my APU was actually started already, and that’s why clicking on the START button did not do anything.
There are two reasons why i thought that the APU isn’t running.
1.I somehow missed the shiny green AVAIL indication on the overhead panel, and there was ECAM message about DOOR being opened, so i couldn’t see the indication that the APU is running.
2.What confused me the most, was that despite the APU was running, the little arrow on the right ECAM screen, stayed pointing to the 0 position, instead of 1 as it should ← shouldn’t it?
IIRC, when i was flying in A320Neo, when the APU is started, the arrow moves from pointing at zero to pointing at one. So that’s why i thought that the APU was either off or malfunctioning somehow.
I had a short pause flying other planes, and when i returned to A310, i kinda forgot about this entire thing, only now realizing what was the cause of the confusion.

So, is this a bug? I mean, the APU arrow pointing at zero even though the APU is running and providing power to the plane.
Thanks for everyone’s help. It was caused by me being slow and ignoring obvious indications that the APU was already running.
Basically i was confused by the confusing indication, trying to switch on something that was already on.