NSEU - CABIN ALTITUDE—Cabin pressure in terms of equivalent altitude above sea level. the oxygen
Ministry_Cork, sorry, I don't understand your point.
Cabin pressure is less at altitude than it is at sea level (or excessive differential would literally blow up the aircraft at higher altitudes). If the pressure in the cabin at sea level is 14.7 psi (or more) at takeoff and the cabin pressure at 40,000ft is, say, 11 psi (7000' cabin alt), did the cabin pressure decrease (de-pressurise) or increase?