A valve assembly includes a nitrogen enriched airflow control valve, a first stage surge control valve and a second stage surge control valve respectively arranged in a passage downstream of an air separation module, and in first and second surge control passages. The valves are in a ganged relationship or connected to one another such they move with one another in response to an input from a common actuator. The surge control valves open as the nitrogen enriched airflow control valve is moved to provide a smaller area.