A developing theme of long-haul operations is the desire for non-stop services between large centres of population and business areas. The delivery of modern aircraft with such long-range capability is evidence of airline commercial objectives and plainly demands improvements to the way in which air traffic is managed. There is now an opportunity to change radically the way in which over-flights are managed and operated. It is imperative to increase capacity in step with demand as it is the limitation in capacity that is fast limiting an expansion of the business.

The availability of an aeronautical mobile satellite service and the emergence of a global navigation satellite system should enable CNS services to be established for civil aviation, virtually worldwide. This paper discusses how the development of a low-cost ADS system, employing these satellite services, might be used to the advantage of European air traffic management (ATM). It indicates that the earlier action is taken, the greater will be the potential benefits. This paper is an updated version of that presented at the NAV94 Conference in November 1994.

In an earlier paper, the writer attempted a quantitative study of a flow-planning system for aircraft intending to fly across Europe. This paper aims to offer each aircraft a clearance giving a reasonable expectation that, throughout cruising flight at least, there will be no conflict with other traffic. Such a clearance is sometimes termed a ‘tube of flight’. Reference i assumed a pattern of traffic flying along rhumb lines, each flight having a starting position chosen at random in a region roughly the size of Europe. Flight was in a random direction and the flight path length was chosen at random from a plausible distribution.

At the present day European ATC is exercised by a multiplicity of more-or-less autonomous control centres. ‘Flow Regulation’ is used roughly to match traffic demand to the capacity of the en-route ATC and of the destination airport. The ATC authority at the point of departure for a remote destination cannot however give any guarantee that the pilot will be able to follow his chosen trajectory. The filed flight plan and the departure clearance have been described as a ‘licence to get into the sky and see what happens’.

A recent paper by Cox, ten Have and Forrester is planned to be the first of a series describing the work of the European Vertical Studies Sub Group (VSSG) set up under the ICAO panel for review of the general concept of separation. The present paper has no connection with the VSSG work.

Primarily in response to airline pressures for fuel economies, ICAO, the International Civil Aviation Organization, established a study programme early in the 1980s to determine the feasibility of halving the vertical separation minimum (VSM) used above FL 290 to 1000 ft. This paper is the first of a 3-part article describing a European contribution to this programme. After outlining the aims and organization of the experimental work, it describes the choice of methodology available to measure height-keeping errors and gives an indication of the measurement accuracy achieved. Details of the data collections, the risk calculations performed and the factors found to affect height-keeping accuracy are given in Parts II and III. Overall, the work has shown that whereas it would be technically feasible to introduce a 1000-ft VSM in the North Atlantic region, other measures would be necessary before it could be used in continental airspace. Today, in certain areas, the need for a reduced VSM has become even more pressing in order to achieve the gains in airspace capacity necessary to handle rapidly growing volumes of air traffic.

Life is more intense today than was shown in the film, and direction finding is somewhat more precise. We now know where aircraft are, rather than where they were some minutes earlier, (for at least most of the time!) and not every air traffic controller we employ speaks like an early BBC announcer.

This paper describes the basic principles of a method developed to guide aircraft accurately down to the runway in a time-of-arrival constrained environment. The method is designed to be used in a ‘zone of convergence’ context or in any similar advanced air traffic control system characterized by the integration of control phases over an extended area on the one hand and true ‘computer assistance’ to the air traffic controller on the other; that is, assistance provided at the decision-making level through the automatic generation of guidance advisories.

The method includes two closely-coupled basic components; namely, a ‘predictor’, which computes a trajectory once initial conditions and plans are known, and a ‘profile manager’, which adapts the plans to meet the time constraints and generates the guidance directives on the basis of present position, actual surveillance information, aircraft operation and route constraints.

A Long-range Secondary Surveillance Radar (LSSR) has been developed and recently used as an Oceanic Route Surveillance Radar (ORSR) in Japan. The LSSR is an SSR (Secondary Surveillance Radar) only system for which the maximum coverage is 250 nautical miles (n.m.). This system utilizes monopulse azimuth estimation techniques for improving the accuracy of azimuth estimation.

The situation today can be described as very frustrating for a variety of reasons. Air traffic flow-management (ATFM) has dominated the scene for many years since its conception in 1980. At that time, the principles of ATFM were directed at ensuring that temporary or isolated sector overloads could be handled by ATC and only when broad, prolonged overloads were expected was ATFM activated. Today, we have the reverse situation, where ATFM is active throughout 16 h or more during each day. The system as such was never intended or planned to cope with such a burden and the results are seen in a variety of forms, including departure delays as shown in Fig. 1.

This, and the following three papers were presented at the Royal Institute of Navigation meeting ‘Management of Air Traffic Flow in Europe' on 15 November 1989.

One of the growth industries in Europe is the production of articles in newspapers and programmes on radio and television which deal with European air traffic control. They usually have titles like, ‘The Crisis in ATC’, or ‘European Air Traffic Meltdown’. Jane's Airport Review, in October 1989, had an article entitled ‘Wanted: One ATC System for Europe’.

The paper has defined the objectives of flow-management, the techniques it uses, its present organization and the existing problems. It has covered the plans which have been made to radically improve the service and has described the final goal as we can see it from this point, together with the interim development phases.