APU sounds running when engines are running and APU switched off

Hello everyone,

First of all I apologise in advance if this has already been reported in a separate topic.

I discovered on both the B737-800 and the A220-300 that the APU sounds are running in the background while the engines are on and the APU itself in the systems page is off. I tested on different aircraft like the A330-300, the A320 and the B787-8 and the issue did not persist on those aircraft leading me to think that it’s A220 and B737 specific or for those aircraft that has an APU in app? I will leave a link to the video of the issue here: APU sound issue - YouTube

Steps to Reproduce

  • Launch the App
  • Spawn in at any airport on a runway with the A220 or B738
  • APU sound should be hearable in the background while engines are at idle and running.

Device and Software Info
Device: Apple IPad Air 3 2019
Software Version: IOS 14.8.1
App Version: 21.8 (1385)


The engine sound has been slightly tweaked, so maybe that’s what you’re hearing (maybe they mixed it with the APU sound)

The thing is, is that it sounds awfully similar to the APU sounds we have on the likes of the B777 and the A330 so I can’t really tell the difference :)

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I noticed something quite similar actually.

I didn’t test this on all aircraft

When I was in the A223, I quickly turned on the Main Battery and APU and before the actual start-up of the electronic system I switched it off.

When I did this the screens didn’t turn at all and most importantly, the sound of the APU turning on continued to play as if the electronic system was turning on.

It’s a weird one alright, I doubt they would’ve used the APU sound to blend it into the updated generic sound

I tested this on solo spawned in on a runway for takeoff when all the systems are fired up, leaving the APU off when it’s no longer needed but yet there is still the sounds in the background. Would love some clarification whether these sounds are linked to the new generic sounds or if it’s a bug.

Although I haven’t heard this myself, it could be because the APU sound heard inside the aircraft is, albeit very quiet, the sound of the air conditioning which would be on while both the APU or the engines are running (as they are both able to power the air conditioning packs).

Ye it’s weird because before there wasn’t a sound for the A/C packs maybe there is now?

Possibly, I’m not sure. IF has always been a bit weird with sounds so it could well be that they’ve just updated the APU sound to make it slightly more realistic and similar to the A/C packs. That would be my guess anyway

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