SubscribeThe automated Air Traffic Control systems TERCAS were designed and built during the time period 1975 - 1981 by the Swedish company Stansaab (later Datasaab) for the airport Mineral'nye Vody, the Kiev TMA, and the Moscow FIR and TMA.
Figure 1: Moscow Area Control Center
The Moscow Air Traffic Control Center was at the time, and remains to this day one of the largest in the world. It comprises:
- Area Control with duplicated FDP/RDP systems, 7 radar stations and 8 AFTN channels serving 30 area control suites, 6 flow planning suites and 1 technical suite.
- Terminal Control with duplicated FDP/RDP systems, 3 radar stations, 4 ADC stations, 4 ADF stations, 4 ARIS connections serving 12 arrival/departure control suites, 6 zone control suites and 1 technical suite.
- One Simulator with 11 trainee/pilot suites, 1 supervisor, 1 technical and 2 instructor suites.
- One Programming Center
- One Central Workshop
The TERCAS systems were built, passed full cycle of acceptance and were turned over to the USSR Civil Aviation branches for regular operation in record time: Mineral’nye Vody in June 1979, Kiev in December 1979, and Moscow in April 1981. Ever since, the systems have proved their high operational availability and efficiency and still do today. In 1994, after 15 years of operation, ICAO experts who visited the Moscow ATC Center testified that these systems remained the most modern in the world regarding volume and the ingenuity of technical and operational solutions implemented.
Purchasing of a completely new system for Moscow ATC is in progress, but the current system will still remain in use at least until 2009. A 30-year old system that still performs satisfactorily – how is this possible?
Part of the answer lies in the capacity and excellence of the system itself; part in the competence and commitment of the staff and management at the Moscow Center. They were deeply engaged in the system from the very start, learnt it thoroughly and were able to take full responsibility for the maintenance, which they have carried out in an extraordinary way over the years. Their cooperation with the Swedish company Si ATM started as early as in 1980, and Si ATM has followed activities at the Center closely ever since and been involved in a number of decisions and enhancements. This exceptional cooperation also helped make it possible to define and realize required upgrading measures in due time.
Upgrading of the Moscow Air Traffic Control Center
The 1990s was the decade when a large number of air traffic control systems designed and developed in the late 1970s reached their capacity limit. Continuous increases in air traffic resulted in problems with capacity and response times much sooner than predicted when they were installed. Also, end-of-life on various equipment caused increased maintenance costs.
In most cases, the replacement of current systems with next-generation systems was still far away, as the process of evaluating, purchasing and implementing a new system is a complex and lengthy one. Many systems must therefore continue to operate for another 10 years or more, requiring the implementation of various measures in order to handle the growing demands on these old systems. Such measures must be easy to implement and economical. In addition, they must not affect the functionality of the system in place.
The Moscow ATC Center was, of course, also facing these problems. In a longer perspective, such problems, although seemingly small, could have made the entire center inoperative – had not staff and managers at the Moscow ATC Center had the technical competence to realize the full extent of the problem and therefore initiate measures when and as required.
The first and major upgrading packages, which were implemented in 1994–1995 by Si ATM of Sweden, comprised:
- Replacement of old disks (Ampex) by modern Winchester disks
- Replacement of old memory modules by a faster type of memory
- Improvement of CPU capacity by speeding up the CPU cycles
- Replacement of old magnetic tape media by new modern Winchester disks
Subsequent upgrading operations have included
- Y2K certification
- Replacement of line printers and strip printers
- Software upgrades
- Implementation of a Radar by-pass system in Moscow TCC
- Upgrading of radar stations
- Extension of radar inputs
- Automatization of a billing system
Needless to say, modifications in systems that are in 24-hour use is very delicate and sensitive work. In order to secure the availability of the running systems and to disturb the operational service as little as possible, the implementation was split into a number of carefully defined main steps, each consisting of equally well-defined sub-steps. This stepwise upgrading turned out to be very successful. Nevertheless, the Moscow Center is facing a change of generations, and the purchasing of a new system has commenced.
The future is likely to be as trying for the Russian authorities as the present situation is for many other Civil Aviation Authorities that are in the process of implementing a completely new system. Systems today are so large and complex that even major suppliers have difficulties handling them. This raises important considerations regarding implementation strategies.
Traditional implementation
Recent history concerning the implementation of ATM systems is a sad story of delays, increased costs, inability to reach initial objectives and even total project collapses. There are many explanations to this negative record, and explanations differ from one programme to another. Some common weaknesses that impair traditional implementation may, however, be identified. Detailed system functionality is negotiated and decided on at a very early stage, in connection with the contract negotiations. The specification thus created will then remain unchanged clear up to the testing phase and, in many projects, the customer will have no real control over or influence on the ongoing work.
The risk is obvious that he will receive a product that does not correspond to his needs and expectations. Maybe the customer and the supplier did not manage to be sufficiently clear and detailed in their specification work. Or maybe they simply had no possibility to foresee the changes that are likely to develop during a lengthy implementation period. And in the end, nobody is happy. The customer asks for more functionality and the supplier for more money. New negotiations cause agitation and interfere with the work already in progress. The delay is already a fact. The collapse is eminent.
Phased implementation
In phased project implementation, a number of phases are defined, and the functionality of each phase is specified very carefully in order to avoid temporary solutions and dead ends. Each phase constitutes a clearly defined completed milestone, possible to use operationally, and the following phase acts as a smooth upgrading of the previous one.
Figure 2 The ATRACC system for Riga FIR, implemented by Si ATM in 1996-1999, is a first-rate example of phased implementation of a new ATC system
Some of the most important advantages with phased implementation are:
- It is easier to control and follow up on a project divided into a number of well-defined phases.
- Buyer and user get tangible, usually high-priority, results early in the project.
- It is easier to get controller acceptance.
- Acceptance testing becomes less dramatic for both parties.
- The transition to the new system is easier to perform.
- There are a number of clearly defined milestones to which payment schedules and other contractual issues can be connected.
- The project risk decreases.
- The customer gets in-depth knowledge of the system hardware, software and functionality.
- The product usability increases.
- The calendar time for operational evaluation can be limited.
Conclusion
The TERCAS system at Moscow Air Traffic Control Center has had a long and successful operational life. The 25-year old system still performs well and will remain in use at least until 2009. This was made possible thanks to excellent maintenance and continuous stepwise upgrading. Nevertheless, the Moscow Center is facing a change of generations, and the purchasing of a new system has commenced. Installing a new ATC system in one lengthy extensive implementation phase is hardly realistic, as systems today are so large and complex that even major suppliers have difficulties handling them in the traditional manner. In view of the serious problems with traditional implementation of recent ATC systems and the positive experiences of phased implementation, we must now ask whether the time has come to apply phased implementation also in new system implementations.
