Capture AFTN Terminal System (CATS)

System Attributes

Windows© based application running on diskless solid-state Windows 10 embedded systems:

Interfaces - bespoke serial and customized TN3270 across Ethernet TCP/IP:

Core processes - OfficeCraft software and libraries written in Delphi.


CATS receives weather forecast information via slow speed serial communications links to maintain a database of predicted upper winds, then, at appropriate intervals constructs and makes available special messages to update a flight data processing system.

Because of the variable input message format used, “expert system” techniques are used to parse and decrypt the weather information supplied by the Met Office.

It is a Windows© application designed to be compatible with any system running under all versions of Windows©. It uses a separate SQL database manager. The recommended implementation uses a dedicated diskless system running Windows© 7 embedded, with an external network connected SQL database manager.

Key Technologies Used

Windows CATS is designed for compatibility with all versions of Windows©.
Delphi The application is written entirely in Delphi and using OfficeCraft Delphi libraries.
Serial Comms A specialized serial interface written using OfficeCraft Delphi library routines.
Ethernet TCP/IP Ethernet connections are used for mainframe connectivity and for system maintenance and support functions.
TN3270 A specialized custom form of TN3270 using OfficeCraft libraries that was developed to interface to several mainframe computers in a very demanding environment.

System Highlights

To accurately predict the progress of air traffic, flight data processing systems require accurate and timely information relating to wind speeds at the appropriate flight levels.

CATS extracts predicted wind speed information from the Aeronautical Fixed Telecommunications Network (AFTN). This is only available via a slow speed, non-secure, error-prone serial link.

The raw data is formatted for transmission by hand, so has to be decrypted using “expert system” techniques. Extensive manual correction capabilities are also provided. All data input is subjected to elaborate and comprehensive checks for content, validity, and credibility prior to its being accepted and stored in an SQL database.

Wind speed advisory messages are then constructed to make the information available to the flight data processing systems. These are transmitted at appropriate times, via a special communications controller; with every message being checked and positively acknowledged by the mainframe system.

In order to meet the stringent safety standards the CAT system includes : -

  • Comprehensive reporting and control via fully configurable GUI and display windows;
  • An ability for data over-ride, including full edit capability;
  • Error detection, processing and recovery processes, including interface monitoring, comprehensive automatic data credibility checking and system exception handling.
  • Automated data logging and retention;
  • Provision for manual inspection of generated message data prior to it being transmitted to the automated systems.

CATS is currently used by the National Air Traffic Services (NATS) operational flight data processing systems.