Patent ID: 8808072

Claim:
A cabin pressure control system comprising: a first outflow valve having a first primary motor controlled by a first outflow valve primary motor driver, said first outflow valve having a first backup motor controlled by a first backup motor driver; a second outflow valve having a second primary motor controlled by a second outflow valve primary motor driver that is not the first outflow valve primary motor driver, said second outflow valve having a second backup motor controlled by a second backup motor driver; wherein upon failure of said first outflow valve primary motor driver, but not the second outflow valve primary motor driver, said system is configured to control said first outflow valve via a sequential control path comprising said second outflow valve primary motor driver, said first backup motor driver, and said first backup motor; and wherein upon failure of said second outflow valve primary motor driver, but not the first outflow valve primary motor driver, said system is configured to control said second outflow valve via a sequential control path comprising said first outflow valve primary motor driver, said second backup motor driver, and said second backup motor, whereby, upon failure of either of the outflow valve primary motor drivers, the first and second outflow valves are controlled through operation of at least one of the outflow valve primary motor drivers.