STCA
Short Term Conflict Alert monitors for loss of separation between two aircraft with a look-ahead time of two minutes. Once the system calculates a loss of separation within this timeframe, it automatically triggers an alert. It also shows a projection of the incident that is bound to happen after two minutes, giving you the time to react before it happens.
APW
Area Proximity Warning works almost the same as STCA, but instead of looking for conflicts between aircraft, it monitors conflicts regarding airspaces. If a pilot is about to enter a restricted airspace within the next two minutes, it will trigger an alert. The System takes into account the current altitude of the aircraft, its flight rule and temporary airspace restrictions.
