An aircraft cabin pressure control system valve integrates three cabin pressure
control functions, main cabin flow control, positive pressure relief, and negative
pressure relief, into a single valve package. The valve includes a control valve
that is used for main cabin flow control, for primary positive pressure relief,
and primary negative pressure relief. The valve can also include a positive pressure
relief valve and a negative pressure relief valve, which are used for backup positive
pressure relief and negative pressure relief, respectively. An actuator for the
valve is also provided.