As Europe tackles another summer of air traffic delays, an independent report of last year's performance points to future relief


With air traffic and flight delays in Europe this summer topping those of the crisis proportions reached last year, 1999 looks set to break more records.

The European air traffic management (ATM) system is saturated, with a small rise in demand causing a large increase in delays, according to Eurocontrol's Performance Review Commission (PRC).

The PRC, comprising 12 independent airline and air traffic control (ATC) experts, was established last year as part of Eurocontrol's revised convention to measure ATM performance in Europe. The PRC was tasked with ensuring "the effective management of the European ATM system through a strong, transparent and independent performance review and target setting system to facilitate more effective management of the European ATM system, encourage mutual accountability for system performance and provide a better basis for investment analyses".

In its recently published first report, the PRC spotlights Europe's troubled ATM system. The commission's role is not to praise or criticise, but to "help everyone involved in effectively improving future ATM performance".

The panel has identified a "top 10" of ATM performance problems (see below), with increased ATC delays in first place. These hold-ups rose by more than 40% last summer compared with the previous summer. "This marked deterioration of the delay situation in 1998 is alarming," says the PRC.

ATC delays in Greece, for example, warranted particular attention because of their effect on those in the rest of Europe. Traffic in Greece during the year was only a fraction of European Civil Aviation Conference Area (ECAC) traffic, but the area generated a high number of hold-ups - 10-15% of the total en route delay minutes - disproportionate to the volume of traffic. "When Greece improves, this top 10 ATM item should become a standing one directed at the lowest performing air traffic service [ATS] provider in the European system," suggests the commission.

Second on the list is the European ATC system's inability to anticipate future traffic growth and implement the required capacity, the PRC says. "European-wide capacity planning and targets will need to be linked with ATS provider plans, which in turn will need to be supported by the appropriate business and capital expenditure plans," it suggests.

Capacity on the ground at airports is also at a critical juncture, with an increasing number of European airports congested at some time of day. Methods to determine and increase capacity at the critical airports must be applied consistently throughout Europe, says the PRC.

The lack of transparency of how airports' landing charges are spent on ATC is cause for concern, while consolidation of some of the 69 area control centres (ACCs) throughout ECAC should be considered, to improve airspace management, suggests the PRC. To date, there has been limited investigation into the merits of operating fewer large ACCs in Europe rather than a large number of small ones.

Improving the system

With increasing traffic levels and with airspace becoming scarcer, airspace management needs to be improved, as do the planning and implementation of European integration programmes.

Although there has been reasonable success in advancing the compatibility of ATC in Europe through the European Air Traffic Management Harmonisation and Integration Programme (EATCHIP), there has been no significant progress in system integration, the PRC believes. "The aim should be to optimise the efficiency of the system as a whole, rather than preserving the interests of individual components," it says.

Because of the failure to implement on time previous programmes, such as basic area navigation, the PRC also expresses concern about the implementation of Europe-wide programmes, such as reduced vertical separation minima (RVSM) in 2002 and airborne collision avoidance systems next year.

Time and cost overruns of new ATC system implementation is another headache. "Throughout Europe, investments of several hundred millions of euros are failing to deliver the expected benefits on time," says the commission.

At number 10 on the PRC's critical issue list is greater emphasis on customer orientation. "ATC services need to respond much more to customer requirements," the PRC urges.

Further, of the10 primary key performance areas identified by the PRC as needing attention to improve Europe's ATM system, the commission has studied three in detail: delay, safety and cost-effectiveness. It is in the area of delays that the PRC analysis of European ATM is most enlightening.

The PRC's study highlights the reactive way in which Europe's ATM system is managed. With remedial actions typically taking five years to show results, a more proactive and forward-looking collective management of the ATM system is needed, the commission suggests.

Judging from the performance of Europe's ATM system last year, the need for the PRC has never been greater. The PRC's analysis comes as Europe's ATM system attempts to cope with unprecedented traffic growth. Since 1985, European traffic has been increasing at 5-8% annually. ATM-related delays have risen, as capacity no longer matches demand, resulting in the delay crisis of the late 1980s. European states took remedial action from 1988, which led to improvements between 1990 and 1994, but the system is again at breaking point.

ATM delays contribution

ATM contributed 30% of air transport departure delays last year. Of this figure, the largest portion - 27.8% - was related to air traffic flow management (ATFM), with a smaller percentage caused by airport ground operations. Waiting queues for every regulated sector and airport are managed by Eurocontrol's Central Flow Management Unit (CFMU). Reactionary delays, such as late departures due to late arrivals, was the largest single cause of departure hold-ups last year, at 37.7%. Those of ATC origin, such as ATFM and airport ground-based delays, accounted for half of all departure hold-ups during the year, other than reactionary delays.

The PRC focused its investigation on ATFM-based incidents. The primary cause of ATFM delay - 75% - is a structural lack of ATC capacity related to en route services, says the PRC. Airport ATC capacity accounted for 9% of the ATFM delays, followed by weather (7%), ground operations at 5%, technical reasons (2%) and other (2%).

The commission's study shows a continued increase in European hold-ups last year, to 17.1% of all flights, from 15.4% in 1997. Over the period, total ATFM hold-ups in minutes rose by 30.7%, the average ATFM delay per flight increased by 24.5%. The average ATFM delay per held-up flight increased by 12%.

En route hold-ups, which accounted for most ATFM delays at 79% of the total, increased by 39.4%, while airport delays increased in line with traffic growth at 6%.

The PRC study highlights ACC performance during the year. Athens ACC suffered the highest average ATFM delay last year at 9min per movement, followed by Macedonia (ACC) at just over 5min, Reims at just under 4min, Amsterdam (3min), Geneva (just under 3min), followed closely by London, Padua, Paris, Milan and Zurich.

Last year, as in previous years, the ATFM delays were concentrated in summer, which is classified by the CFMU as 4 May-1 November. En route ATFM delays peaked around week 26 of the year and then declined. At around week 27 there is a "learning effect", according to the PRC, whereby delays decline while traffic increases.

"This would indicate that, as experience is gained, the capacity is expanded. Furthermore, the same trend has been apparent in previous years. The question arises as to why an increase in capacity cannot be achieved earlier in the year," says the PRC.

ATFM delays also sharply increase at weekends, when traffic is lower than on weekdays, the PRC report reveals. The PRC says that it is not clear why overall ECAC capacity is less during weekends than on weekdays, although the different structure of traffic patterns, with average flying time being longer at weekends, and a different concentration of traffic could have an influence.

Furthermore, as traffic volume increases, the delay elasticity - the percentage rise in ATFM en route delay for each 1% increase in traffic volume - becomes greater, says the PRC. At the average 1998 volume of 20,550 flights a day, the delay elasticity was 6.7, while at high traffic volumes of 23,000 flights a day, the elasticity was 7.5. "The ATM system is tightening up as the imbalance between supply and demand grows," says the PRC. The worsening situation is not related to a unique cause. A number of factors contributed, the panel believes.

The PRC has identified a "backbone" area in Europe which generates most of the delays. This consists of three regions: London area control centre, "area north" and "area south". Area north comprises northern France, Belgium, Luxembourg, western Germany and the Netherlands, while area south includes south-east France, northern Italy and Switzerland. Last summer, this backbone accounted for 53% of the en route ATFM delays and 59% of the delayed flights, says the PRC.

"Because the 'backbone' area is at the heart of Europe, most flights cross this area. A shortage of capacity in any of these areas has a significant impact across the whole of Europe. Careful planning and implementation of capacity is required in particular in the 'backbone area' to avoid major disruption," the PRC suggests. Initiatives may be necessary at ECAC or multinational level because the interaction between the ACCs in these regions is so high, it adds. The three areas also accounted for most delays in 1997.

The PRC also found that just 100 sectors, or 24% of all sectors, contributed 90% of the total en route AFTM delays during the period. Fifteen sectors, or 3% of all sectors, contributed around 45% of AFTM en route hold-ups for the period.

A major contributory factor to the worsening delays was that, although individual capacity targets set by Eurocontrol to cope with the traffic growth were met or exceeded by some ACCs, there was no measurable increase in overall capacity in the region. Forecasting at ACC level is not straightforward as increases in capacity have to be planned and implemented, says the PRC.

Unexpected traffic growth

In the late 1980s, traffic growth was largely unexpected and traffic was 10-15% above the baseline forecast. Since 1990, it has continued to grow at a constant rate and is within 5% of the baseline forecast, made three years in advance. The PRC notes, however, that traffic growth has been at, or slightly above, the high forecast in the past three years, which means that last year's traffic was within the upper bound forecast three years in advance.

In 1997, Eurocontrol set capacity targets for states to meet the expected traffic demand last summer, when a target of 7% increase in overall capacity across the ECAC area was set. "This means that 7% more traffic should have been handled with no additional ATFM delay," says the PRC. A capacity plan was established for the critical European ACCs for the summer. While many ACCs, including Barcelona, Geneva, London, Maastricht, Madrid, Marseilles, Milan, Padua, Paris and Zurich, increased their capacity, other critical centres, including Athens, Budapest, Karlsruhe, Macedonia and Reims, were unable to follow suit. Although capacity increased in some ACCs, there was no measurable overall increase in Europe. This "shows the importance of some form of collective management of the ATM system at European level", says the PRC. The commission also suggests that capacity planning should have started sooner for last summer. "Since future traffic growth is uncertain and, given the high cost of delays, it would be wise to plan for some excess capacity or to develop the ability to deliver extra capacity at the right time and at short notice," the PRC suggests.

Insufficient capacity in some areas resulted in a major delay increase throughout Europe. Traffic growth was below target, at 4.8%, and total ATFM delay up by 42.4%. "This situation is becoming comparable to the crisis situation of the late 1980s, when delay performance reached an unacceptable level," says the PRC. In 1989, the average delay per flight was 4.3min, while the average last summer was 5min.

With Europe's ATM system handling at least 25,000 air traffic movements daily this summer, delays this year are set to be even worse than last. Eurocontrol is focusing on sector and ACC trouble spots, reorganising Europe's route structure to remove traditional bottlenecks, and is close to implementing airspace capacity providers such as RVSM. But, with air traffic levels at the system's capacity limit in many ECAC areas, only revolutionary measures to provide increased capacity will ensure Europe's ATM system avoids future summer crises. Eurocontrol outlines these measures in its ATM-2000+ Strategy, but the air navigation organisation believes that implementation must start now. Otherwise Europe will never be far from ATC crisis. Top 10 Air Traffic Management performance problems 1 - Increase in air traffic control delays.

2 - Inadequate capacity planning and implementation.

3 - Inadequate capacity at critical airports.

4 - Lack of transparency of ATC cost base.

5 - Need to rationalise area control centres.

6 - Poor management and use of core European airspace.

7 - Poor planning and implementation of European integration projects.

8 - Inadequate decision-making processes.

9 - Time and cost over-runs of new ATC systems.

10 - Need for greater emphasis on customer orientation.

Source: Flight International