Short-term conflict alerts (STCA) provide controllers with a short-term warning of potential conflicts between aircraft in the same airspace. Enhancing the STCA safety net with information down-linked from the aircraft provides more accurate data on which to base warning signals.

Aircraft already transmit enhanced surveillance data using Mode S. SESAR developed Solution #69 "Enhanced short-term conflict alerts (STCA) with downlinked parameters" that incorporates two Mode-S derived parameters into the STCA logic: selected flight level and track angle rate. The former prompts the system to check if the aircraft intends to climb or descend to a certain flight level even before it begins the manoeuvre. This can detect an unsafe clearance given in error by the controller, or controller-pilot misunderstandings in radio transmissions, such as read back errors or instructions copied by a different aircraft. The latter - track angle rate – gives a better anticipation of how an aircraft will turn, and applies particularly in terminal airspace.

This SESAR solution #69 is now implemented in Austria, Germany, Denmark, Ireland, Moldova, Malta, Maastricht UAC, Poland and planned in 5 other ANSPs