A320 - APU BLEED PRESS INDICATION

[100.above]

Hello There,

So the books say amber XX's will be shown if ADIRS2 is N/A or OFF or if signal from ECB is invalid/not sent.

• does anyone know what it is actually referencing from the ADIRS?
  
• Is it using a static pressure or something as a reference?

You would think a pressure sensor would be something simple and independant.

Another funny thing is if I compare 2 different FCOM's I have found, one being recent 2012. The 2012 one says it uses ADIRS1 and the old ones on smart cockpit state ADIRS2.

Fairly useless thing to know but I cant help to ask out of interest!

[gAMbl3]

For 320(classic) its ADIRS2 whereas for 319 and 321(enhanced) its ADIRS1

[rudderrudderrat]

Hi 100.above,

You would think a pressure sensor would be something simple and independent.

It is. It simply measures the total pressure.
In order to display the Delta pressure, the system needs to know the ambient Pressure also.

[100.above]

Hi rudderrudderrat & gamblr3,

Thanks for your responses!

Makes sense now

Did you guys look at an engineering manual or something to find this out?

[AVApilot]

Delta pressure

Hello Rudderrudderrat,

You say that "In order to display the Delta pressure, the system needs to know the ambient Pressure also." But the APU system page does not show any kind of delta pressure, I'm confused, maybe you can elaborate a liitle more?

Thanks in advance.

[rudderrudderrat]

Hi AVApilot,

It looks like this:


Note 3
or like this

[Silky]

To register any pressure indication it firstly requires a reference pressure which is what you get once ADIRU 1/2 is turned on as they then power the static system!
HOPE THAT HELPS

[rcmoraes]

i've noted that with all ADRs off you wont have the bleed indication on the apu page, but you whill have it on the bleed page (apu supling). any ideas why ?