Short-term conflict alert (STCA) is an automated warning system for
air traffic controller
Air traffic control specialists, abbreviated ATCS, are personnel responsible for the safe, orderly, and expeditious flow of air traffic in the global air traffic control system. Usually stationed in air traffic control centers and control ...
s (ATCO). It 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.
Description
ICAO Doc 4444 requires that radar systems should provide for the display of safety-related alerts including the presentation of actual and predicted conflict.
It is worth mentioning that ICAO Doc 4444 does neither provide definitions of the term STCA nor ''conflict alert''. Instead the term STCA is ambiguously used in
ATC community to identify such alerts as well as for data processing systems providing the alert function.
As an implementation STCA is part of the predictive safety net functions. It uses surveillance information derived from
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
s,
ADS-B or
multilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth (geopositioning).
When more than three distances are involved, it may be called multilateration, for emph ...
as well as environmental data and optional
flight plan
Flight plans are documents filed by a pilot or flight dispatcher with the local Air Navigation Service Provider (e.g. the FAA in the United States) prior to departure which indicate the plane's planned route or flight path. Flight plan format is ...
information in order to predict the movement of aircraft. This process is usually working unnoticeably to the air traffic controller unless a (potential) separation infringement is identified. In this case STCA will generate an alarm to inform the air traffic controller about the hazardous situation identifying the conflicting aircraft.
Due to the uncertainty of trajectory prediction the look ahead time of STCA system is typically limited to approx. 2 minutes.
Extending the look ahead time is not beneficial as more and more nuisance alerts will be generated.
Related systems
In extend to STCA other ground-based safety net functions are typically implemented to support the ATCO. These in include
* ''
Minimum safe altitude warning
Minimum safe altitude warning (MSAW) is an automated warning system for air traffic controllers (ATCO). It is a ground-based safety net intended to warn the controller about increased risk of controlled flight into terrain
In aviation, a control ...
'' (MSAW); and
* ''Area proximity warnin''g (APW), sometimes also called ''danger area infringement warning'' (DAIW).
The equivalent system on board an aircraft is
TCAS. This system alerts pilots to possible conflicts, and suggests remedial actions, in the form of a climb or descent. Unlike TCAS, STCA does not normally suggest remedial action. If action is required, the controller will normally give a turn command to the aircraft, eliminating the possibility that his command will contradict that given by TCAS.
Other concepts of air safety are:
* making a
flight plan
Flight plans are documents filed by a pilot or flight dispatcher with the local Air Navigation Service Provider (e.g. the FAA in the United States) prior to departure which indicate the plane's planned route or flight path. Flight plan format is ...
and
* using
airways.
See also
*
Eurocat (Air Traffic Management System)
The TopSky (formerly EUROCAT) system is a computerised air traffic control and management solution developed by Thales Air Systems (formerly Thomson CSF). It utilises a distributed computing architecture and is capable of integrating geographica ...
References
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External links
SKYbrary article on STCA
Aviation safety
Air traffic control
Warning systems