setting pressurization - how to? avoiding the red "cabin alt hi" warning

[APbjoern 1]

Hey there,

 

could anybody help me to understand avoiding the red "cabin alt hi" warning?

 

Thnx

Bjoern

[Jim Robinson 122]

There's a dial on the console where you set the cabin altitude before takeoff. Click/drag or roll your mousewheel on the right knob to adjust. The airplane loads in the sim with that dial set to sea level (8' actually). The fuselage can structurally withstand 5 PSI differential pressure so if you leave the cabin altitude at sea level that pressure will be reached at about 13,000' and the light will come on to tell you the pressurization system isn't capable of maintaining the target cabin altitude. (the outflow valve is dumping air to keep the fuselage from exploding although this is not modeled)

 

IIRC:

 

cabin altitude of 8' - light comes on at about 13,000'

cabin altitude of 8000' - light comes on at about 23,000'

cabin altitude of 10050' (max) - light comes on at about 27,000'

 

Jim

[fppilot 4,355]

Jim explains the warning and cause well.  

 

Below is a link to a good video on the subject of setting the pressure controls...  

 

It would also be helpful for you to have a reference like this available.  This one is from the operations cheat sheet I put together for the Turbine Duke v2.  Note that this one ends at the Turbine Duke's service ceiling.

 

Cabin       0.5       1         2        4          5          6        7         8        9         10        10.5

Aircraft    10.0    11.5    12.8    15.0    17.0    18.5    20.0    21.6    23.0    25.0      25.9

 

I routinely during pre-flight set the Cabin altitude (in thousands) to correspond to my planned cruise altitude, and for the Duke I set the Cabin Climb Rate to a value of approximately 1/3rd of my planned rate of climb.  In the Turbine Duke I routinely climb at a rate of about 2,400 FPM so I set the Cabin Climb Rate control to 800 or 850.

 

Video link:

https://www.youtube.com/watch?v=-e_36SS6FU0

[APbjoern 1]

Thanks Gentlemen :-)

[Jim Robinson 122]

You're welcome Bjoern. :smile:

 

 

It would also be helpful for you to have a reference like this available.

 

Good idea on the chart Frank, I just made one for the C90 GTX.

 

Cabin       0      1      2      3      4      5      6      7      8      9     10
--------   ----   ----   ----   ----   ----   ----   ----   ----   ----   ----   ----
Aircraft   11.4   12.7   14.1   15.5   17.1   18.7   20.2   21.7   23.4   25.0   26.9

Note the cabin altitude selector maxes out at 10,057' which just barely allows you to cruise at FL270 under most atmospheric conditions, lol.

 

Jim

[fppilot 4,355]

Good idea on the chart Frank, I just made one for the C90 GTX.

 

Very nice formatting in that post Jim.  I struggled to get what I got....

 

Mine is part of this....  Have one of these made up for the earlier Carenado C90 as well... but do not have an image of it to upload from my photo site.  Sure you get the idea however. Have them sized, printed, and laminated in knee board size.

 

 

 

Back side:

[Jim Robinson 122]

Well the formatting wasn't exactly coming out like I expected so I just slapped the code tags around it, all the while wondering how you managed to pull it off, lol. Also, I just happen to have the T. Duke too so consider those reference charts stolen! Very nice and thanks!