Air Traffic Control Equipment and Systems
Domain 8 tests the equipment behind the display: surveillance, communications, navigation aids and automation. Questions usually ask what a system can and cannot prove, so focus on identification, coverage and serviceability rather than on manufacturer names.
Surveillance
Primary surveillance radar uses skin returns and gives position but not identity. Secondary surveillance radar interrogates transponders; Mode S provides selective interrogation, aircraft identity and pressure altitude. ADS-B Out broadcasts position and other data. Multilateration uses multiple receivers. Radar separation requires identified surveillance coverage; a primary return alone does not establish identity.
Communications and navigation
AFTN and AMHS carry operational messages. VOR, DME, NDB and ILS provide navigation guidance; NOTAMs warn of unserviceability. Automation such as flight-data processing helps, but the controller remains responsible for the clearance.
Worked example: the display shows a primary return at 5 NM from another aircraft, but no SSR or ADS-B symbol. You have not identified the aircraft, so you cannot apply 5 NM radar separation on that return alone. Obtain identification by transponder, ADS-B or position report, or apply procedural separation until identification is established.
Traps: assuming a displayed symbol is identified traffic; applying radar separation in a known coverage gap; ignoring a navaid NOTAM; confusing Mode C altitude with Mode S identity data.