[BUG] Pressurization behaviour

Dear Asobo, It seems to be an odd behaviour with the pressurisation control
under MSFS. After setting the design_cabin_pressure for my aircraft as 10.3
PSI (9500 feet) and the max_pressure_differential as 5.6 PSI. The MSFS
internal core is setting the PRESSURIZATION CABIN ALTITUDE GOAL to the maximum
regardless of what altitude the aircraft is flying… this combined with a hard
codded maximum climb rate of 500 feet per minute causes lots of issues: 1) If
you flying below the ceiling limit, for example instead of 30,000ft, you are
at 20,000ft the airplane is still trying to pressurize to a cabin altitude of
9500 ft. This is incorrect, it should pressurize to a lower altitude, 9500ft
is the maximum it can do it, it should get there as the aircraft reaches that
altitude instead of pressurizing always to this altitude. 2) Since the max
climb rate being used by the MSFS core is about 500fps or -500fps. This is too
low for many climb profiles, causing the pressurization to fall behind. 3)
Because 1 and 2, you end up with an unrealistic PRESSURIZATION PRESSURE
DIFFERENTIAL, in my case the max should be 5.6, and during a climb you can end
up way above 5.9 PSI sometimes 6.0 PSI. 4) When an airplane is spawn at
cruise, there is no way to set the cabin altitude pressurization to a desired
level. So for example user selects on the MSFS map to spawn at cruise, the
cabin press altitude is now 0, causing alarms all over the place until the
press system can catch up. 5) Even when bleed air is disable pressurization
continues to takes place, this shouldn’t be the case as far as I understand. I
had no other option to resort to write my own custom Pressurization simulation
to avoid the issues above, my objective reporting these issues it to help to
improve the SDK and help future developers to avoid hitting the snags I found
this week. However please note I also encountered bugs with the Pressurization
SDK events and will be posting those via different topics so they can be
tracked properly by the team. Couple of questions if I may: * Is there a way
we can configure the max climb rate for the pressurization control? I could
not find any setting anywhere in the documentation for this. Ideally we should
be able say what is the max climb rate any given aircraft is able to perform.

  • Is there a way we can configure the pressurization cabin altitude goal
    depending on aircraft altitude? something like a curve would be ideal. * Is
    there a way we can set the cabin altitude directly inside the .FLT files?
    otherwise as you might appreciate, any flight started from the map in the
    middle of the air, well cannot be setup correctly. Thanks for any help, Raul

Ideally, instead of a target cabin altitude, we should have a target cabin
differential. That way you get a constant differential pressure between cabin
and aircraft and stopping the climb at 20,000ft in your example would give a
cabin altitude of around 4,750ft. Even better would be a target cabin
differential table vs a target cruise altitude for the aircraft. We could get
variable pressure differential targets for different aircraft altitudes.

Yea, Well that could work too, but we need something to help devs to weak this
better in accordance with each aircraft performance… I ended doing my own
custom simulation using interpolation data based on the Aircraft
pressurization tables at my disposal however is far from perfect given the
little tools I have at hand at the moment. Best, Raul

Ok, after some time playing with everything the only way to manipulate thing
is via the events cabin rate_inc / dec and cabin goal inc / dec. You have to
execute the events until your desired values are in place to manipulate the
pressure, cabing altitude, etc. Hope this helps other developers. Best, Raul

@FlyingRaccoon I have looked into the pressurisation bug and it seems to be related to the cabin altitude difference or pressure differential.

If I don’t set the climb rate manually and leave it to the default 500fpm of the game, it works fine. However, if I try to set it to 600fpm manually, it gets tied to the plane’s vertical speed. So if I’m climbing at 1000fpm, the VS will be 700fpm, no matter if I set it to 500 or -1000.