Automatic cabin pressure control for aircraft - with dual controls for added security and with rate of pressure change modulated

摘要

The cabin pressure in the aircraft is monitored by two sets of pressure instruments, interlocked for a fail-safe operation. A primary control monitors the cabin and outside pressures and equalises the two while a secondary control monitors the rate of pressure change of the cabin and takes over the control when the rate exceeds a set value. The secondary control provides a modulated rate of change for the comfort of the passengers. The cabin pressure drop is limited to a set value below the sea level value for comfort and oxygen supply. Failure of either system ensures that the remaining one assumes full control.