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. In this SESAR solution, two Mode-S derived parameters were incorporated 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. STCA with downlinked parameters was tested for both en-route and terminal airspace environments.
The validation results confirmed the benefits in terms of reduction of nuisance alerts, while relevant alert rate was maintained or increased. Thus, controllers’ trust in the STCA system increased. There was also evidence of improvements in alert warning time within the en-route environment as well as terminal airspace, chiefly due to the anticipation of the vertical evolution based on the downlink of the selected altitude.
This solution is implemented across Europe in the following countries: Austria, Czech Republic, Denmark, Germany, Montenegro, Poland, Romania, Serbia, Switzerland, Turkey, and the UK .
SJU references: #69/ Release 3
Benefits
- Enhanced safety through reduced false alert rates and improved warning times of conflicts between flights
- Improved operational efficiency
- Increase of controller’s situational awareness
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