Under Pressure (but not enough) - cabin pressure at FL280

[Altimutater]

Hi folks,

Can I get some guidance on this - I'm cruising at FL280, I've selected a cabin alt of ~9500ft to match, air sources are set to Both, but the cabin alt is stable at 11,000ft? Man Press Cont doesn't change the cabin pressure no matter where I put it, and I've returned it to approx its centre position. Is there anything I'm missing here?

[Ch.Cole]

That's indeed strange. What are your power settings? maybe the engines can't provide enough bleed air pressure?

[Ch.Cole]

Just as a follow up: I did a test, and I managed to get sufficient pressurisation at FL280. Is it possible that you reduced the RPM below min cruise? One of the peculiarities of the MU2 is that min cruise is 97%. When I reduced it lower to test, the cabin altitude increased. So maybe that was the issue?

[rosseloh]

I had the same issue when flying above roughly that altitude. I did check my engine instruments and all were within (real world) limits for the altitude I was at - but I think the sim model isn't putting out enough bleed pressure to keep the pressurization where it should be (by the book). I reported this in my old bug thread from last year, but of course Tom has been busy.

 

For now it does seem that you have to run the RPM higher than you're "supposed to", if you want to cruise that high, at least the last time I flew.

[Altimutater]

I'll double-check what my min cruise preset gives me - I thought it was 98% but it might be 96%. If it happens again I'll inch up the RPM and see if that helps!