Short-term conflict alert (STCA)

STCA acts as a “safety net” within the air traffic control system – the main tool used for the management of flights crossing the Netherlands at high altitude (up to flight level 245, or 24,500 feet) – by warning of potential losses of separation shortly before they actually occur. It only produces alerts, however, and does not resolve the situation.


Air traffic controllers themselves are primarily responsible for detecting possible losses of separation. In the photograph below, the white lines are so-called “speed vectors” indicating the expected positions of the aircraft concerned in one minute’s time. Because these are converging, a loss of separation is possible unless the controller issues instructions to keep the flights at a safe distance from one another.