Hi All, I just had a thought, I flew from EGKK to EGPH, I set my cruise altitude at FL280. However, looking at my CAB ALT on the lower ECAM it shows 4300 FT, surely that’s not correct? As I understood it the standard cabin pressure should be 7,000 - 8,000 feet, I know it’s around 6,000 feet on the Dreamliner. Anyone can confirm or is this just another small bit of inaccuracy from MSFS 2020.
Cabin altitude is not fixed at a constant level at higher aircraft altitudes. The primary goal of a pressurization system is to insure that the differential pressure (the pressure difference between the inside of the aircraft cabin and the outside atmosphere) does not exceed the structural limits of the fuselage.
I don’t know the maximum allowable differential pressure for an Airbus, but for most airliners, maximum differential pressure will typically be somewhere in the range of 8 to 9 p.s.i. (pounds per square inch). In standard atmospheric conditions, the absolute pressure (outside the airplane) at 28,000 feet is 4.7 p.s.i. If the cabin altitude is 4300 feet, that equates to an absolute pressure of 12.5 p.s.i. The difference between the two (12.5 - 4.7) is 7.8 p.s.i.
So, a cabin altitude of 4300 feet at 28,000 feet aircraft altitude is reasonable and realistic. You won’t see cabin altitudes get into the 6000-7000 foot range until the aircraft gets higher.
Yes, usually 6000 to 8000 ft at maximum certified altitude, you are far below that. 4000 to 5000 ft at FL280 seems reasonable, what does the differential pressure look like?
@HalberQuacky you beat me to it. Your post is more elaborate, ignore this one 
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Ah thanks, guys, yes makes sense
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