Cabin and airport pressure
 

Normally the airplanes are supposed to keep cabin pressure at or below 8000 feet at all times. If it exceeds 10 000 feet, there is warning horn, and at 14 000 feet, masks in cabin drop out.

What happens, however, if the originating or destination airport is located near or above 8000 feet?

Generally for Boeing aircraft the maximum airport elevation for takeoff and landing is just above 8000 ft, so for airports less than this altitude it isnt a problem for airports above this altitude the aircraft requires certification for operations outside the normal environmental envelope!

Mutt