Military service is voluntary, though conscription may occur in wartime. In a significant move for modernization, Hungary decided in 2001 to buy 14 JAS 39 Gripen fighter aircraft for about 800 million EUR. Hungary bought two used Airbus A319 and two Falcon 7X transport aircraft. Three C-17 III Globemaster transport aircraft are operating from Pápa Air Base under Hungarian nationality mark but are maintained by the NATO Heavy Airlift Wing (HAW). In 2017 Hungary signed a contract to buy 20 new Airbus military helicopters and ground attack bombs for the Gripens. Hungarian National Cyber Security Center was re-organized in 2016.