Description

Short Term Conflict Alert (STCA) is a ground-based safety net intended to assist the controller in preventing collision between aircraft by generating, in a timely manner, an alert of a potential or actual infringement of separation minima. Generally, it is more difficult to optimise Short Term Conflict Alert (STCA) for Terminal Control Areas (TMAs) than for en-route airspace. This is because the nature of TMA operations makes it hard to tune the look-ahead parameters used by STCA to predict potential conflicts.

The reason for this is two-fold:

1. TMA traffic is more closely spaced than traffic in en-route airspace; and
2. TMA traffic undergoes far more turns in comparison to en-route traffic – often for much shorter periods of time and at higher rates of turn.

These two factors can result in relatively poor warning time performance and a relatively high number of STCA nuisance alerts in the TMA.