Pressurization Control System
|Primary and Secondary Outflow Valves|
Location - The outflow valves are located in the aft cabin at the bottom of the aft pressure bulkhead.
- The primary outflow valve is electrically controlled by the cabin
pressurization controller and pneumatically driven. The primary
outflow valve incorporates two normally-closed solenoids: climb and
dive, and an integral vacuum ejector. Compressed air and
vacuum are used to drive the primary outflow valve. The
secondary outflow valve is pneumatically connected to the primary
outflow valve, forcing the secondary valve to duplicate the action
of the primary valve. The controller varies the position of
the outflow valves toward open or closed by momentarily energizing
open either the climb solenoid to raise the cabin altitude (decrease
cabin pressure) or the dive solenoid to lower the cabin altitude
(increase cabin pressure).