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Michael Moe

The Yellow Zone

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Just because i am a little bored now that i have completed everything that FS2CREW has to offer( and you really should extend your flight with this if you have the NGX BTW) i was wondering a little about the yellow zone in the cabin pressure system.

 

I often have the needle in this because i fligh high (above FL380) but do it really matter at all ? (also in respect to real life off cause)

 

Thanks

 

Michael Moe

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I've noticed this too, and while I can find the maximum or red line value in the limitations (FCOM L.10.4) listed as 9.1 psi, I cannot find reference to the yellow band that appears to extend from 8.2 to 9.0 psi.  There is a reference to normal operation under certain conditions at 8.35 psi differential pressure (FCOM 2.40.6), which is slightly into the yellow band and is what I've often observed.  I notice my current flight in progress at FL410 is indicating a dP 8.2 psi right at the bottom of the yellow rather than into yellow; which is explained in the FCOM as related to landing altitude. My landing altitude is 49 ft MSL.  The amber caution light is triggered at 8.75 psi among other factors.

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Hi,

 

The yellow (caution) range starts at 8.35psi, as this is the differential pressure that will be scheduled when the aircraft is cruising above FL370, and under normal operations this wouldn't be exceeded. In reality, the needle can sit a tiny bit into the yellow arc.

 

Dan, at FL410 with a landing altitude of 50' set, it should be scheduling an 8.35psi differential. The lines on the gauge are 0.2psi each, so you may be reading 8.4 as 8.2. You are correct, at 8.75psi and no controller response, you'll get an AUTO FAIL caution, and automatic switching to the opposite pressurisation controller will occur. At 9.1psi the relief valve will open.

 

Hope this makes sense.

 

Mike Archer

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The lines on the gauge are 0.2psi each, so you may be reading 8.4 as 8.2.

 

yeah, probably parallax error..., thanks.

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I watched this on my last trip.  Cruising at FL400 with 650' set as the landing elevation the PSID was right at the bottom of the yellow arc, 8.35.

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