Hi all,On climb out and after a short cruise,leaving all bleed switches off,how can I have a 7500 foot cabin alt at 24000?yes it is climbing at 2000fpm,but shouldn't it be close to aircraft altitude?As soon as I placed the pack switches from off,to auto,I got the master caution, and mask drop in the cabin.Is this normal ops?

No, there is something strange, I'll check it ;)

Cabin Altitude should never be above 8000.Why would you be flying with no bleeds on and the packs turned off ?Fred.

Cabin Altitude should never be above 8000.Why would you be flying with no bleeds on and the packs turned off ?Fred.

I agree with Fred here... I also note you have set to manual and not auto - do you have a failure there or just enjoying a physical wrist work out open & close all day ;)

Maybe it's a test I think, or he forgot them off but then he found that altitude in the cabin had something wrong :)Test things that are not allowed or dangerous in real life are other good things of a simulation.

The rate is right as it isthe cabin is climbing and will reach the flight altitude if nothing changes in your panel setup. It will reach soon the altitude warning intervention at 2000ft/min from 7500ft to 10000 in half past a minute (warning), 14000 a bit later (masks)However I'll try it.Cabin climbs, pressure reduces, cabin descend, pressure increase.

It was a test,to see if the 10000 foot master caution would illuminate.

I made a test, all worked fine for me.I took off with packs off, my crz alt for tis test was fl270.Pressure was climbing as expected with packs on for the initial part of the flight, (outflow valve almost closed), reached crz altitude with a good pressure inside, within limits.Then I opened manually the outflow valve, cabin altitude sounded correctly at 10000ft cabin altitude, and no master caution (as it must be).At above 14000ft oxy masks deployed with OXY MASK ON light and OVERHEAD Master caution. as expected.So, system appear to work correctly.