Links2Go Air Traffic Control

The Center-TRACON Automation System, or CTAS, is a set of tools designed to help air traffic controllers manage the increasingly complex air traffic flows at large airports. The tools in CTAS benefit air traffic controllers by reducing stress and workload, and benefit air travelers by reducing delays and increasing safety.

CTAS is more than a set of tools. By combining the skill of controllers with computer generated advisories, the CTAS environment inaugurates a new approach to air traffic control, referred to as human-centered automation. In human-centered automation, controllers increase both their effectiveness to manage complex traffic situations and their awareness of the evolving traffic situation, while retaining their traditional responsibilities for control and safety.

CTAS was conceived and is being prototyped at the NASA Ames Research Center. In 1991 it was chosen by the Federal Aviation Administration (FAA) as the future automation system for the terminal area. In a unique design process, scientists, engineers, and controllers combined their talents to create the algorithms, software and human interfaces in CTAS, fashioning them into tools that controllers can use effectively to solve complex traffic problems.

What are the fundamental technical innovations that make CTAS work? First and foremost is a technique for computing and predicting aircraft trajectories with high accuracy in real time. In CTAS, this technique is embodied in a large and complex software algorithm referred to as the trajectory synthesizer. Second is an algorithm for scheduling aircraft to land at runways with the least possible delay. Third are methods for communicating between CTAS and controllers through special graphical interfaces. These three innovations--together with radar tracks and weather data--are brought together in a complex real time software system that generates CTAS information.

The development of CTAS should not be confused with FAA's ongoing effort to replace the obsolete and failure-prone infrastructure of the current air traffic control system. While that effort is independent of the CTAS development, the new infrastructure, especially color display consoles for controllers, will be highly beneficial for implementing advanced CTAS tools still in laboratory development.

CTAS is a work in progress. NASA and FAA are installing prototype CTAS tools in several stages at air traffic control facilities serving the Denver and Dallas/Fort Worth airports. At these sites, CTAS tools are being evaluated by controllers who are using them in the management of arrival traffic. All three major tool sets in CTAS, which are the Traffic Management Advisor (TMA), Descent Advisor (DA), and Final Approach Spacing Tool (FAST), have undergone initial field evaluation at these airports. However, much additional field testing, as well as laboratory development, must still be done before the full potential of CTAS is realized.

This CTAS Home Page will keep you informed with up-to-date information on news items, progress reports, and technical developments concerning CTAS research and technology.

Heinz Erzberger, Ph.D.
Senior Scientist for Air Traffic Management

CTAS Will Increase Airport Capacity

Listen to a message from Dr. Erzberger. You will need the free RealPlayer.

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Listen to ``Welcome to CTAS!'' as read in various languages by our diverse group of CTAS researchers and developers. You will need the free RealPlayer.

English transcript

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