Hi,When the plane is on the ground, and I switch pressurization to manual mode, fully close the outflow valve, and then switch back to normal or altn mode, the plane pressurizes the cabin for a few seconds, and then depressurizes it. Is it some kind of system check?btw1 - FCOM documentation on pressurization is scarce at the very least; there is even no depiction or explanation of the cabin alt and press diff panel, or am I missing something?btw2 - I was delighted to see how opening doors changes pressurizationbtw3 - am I right there is a small bug there - the pressurization system should not be able to to the above thing, when packs are off?cheers,Jakub

I don't know if there are newer systems installed, but the ones I know have the rate of climb indicators fully mechanical, so, the pointer moves only with a real differential pressure. This with aircraft powered or not. I noticed that on the NGX the rate of climb does some "tests" when you power the aircraft, and the pointer will move in climb and des. directions and then come back to 0. It is a minor issue, and after a second or 2 it is finished.It seems that this happens also if you try to close manually the outflow on ground with packs off... Yes, it seems a bit strange...Maybe it could be related to the real simulator where the indicator is not mechanical (as there is no cabin climb) and maybe the simulator moves in that way, but I'm not sure.For sure, the real one has no this indication.Small issue, but present.

About the double indicator, also if there are no info on the FCOM, you must follow the placard under the panel (in manual mode) and always check the differential pressure that must not go to the yellow or red arcs.

Hi Andrea, thanks for the answer!

I don't know if there are newer systems installed, but the ones I know have the rate of climb indicators fully mechanical, so, the pointer moves only with a real differential pressure. This with aircraft powered or not. I noticed that on the NGX the rate of climb does some "tests" when you power the aircraft, and the pointer will move in climb and des. directions and then come back to 0. It is a minor issue, and after a second or 2 it is finished.

Interestingly, the differential pressure also changes, so the moves of the pointer seem to only reflect this.Jakub