In Europe there is little data available on runway incursion incidents, but available evidence suggests the threat is just as great as in the USA

Any illusion that the runway incursion problem was really only a US issue was dispelled on 8 October last year when a departing SAS Boeing MD-87 thundered into the fog at Milan Linate Airport, oblivious to a business jet which had strayed on to the active runway. In the wake of the loss of both aircraft, all 114 on board and four airport workers, European airport and air traffic authorities were left pondering a stark lesson in their own vulnerability to the incursion menace.

Ironically, the pan-European air traffic management (ATM) body Eurocontrol had set up a Runway Safety Task Force just three months before the Linate collision to boost research into the incursion problem. This month, the agency is scheduled to hold the latest in a string of meetings to assess progress on the year-old programme. It hopes the effort will generate enough data to allow it to build a solid anti-incursion strategy, and lead to an initial set of runway safety recommendations as early as September this year.

"Very little data exists on runway safety occurrences in Europe ," says the organisation. "No safety trend can be identified from the limited statistics and the need for a deeper understanding is apparent." Eurocontrol member states collectively reported just 48 runway incursions for 1999, a figure typical of the previous decade. Safety Regulation Unit head Peter Stastny says that, while runway safety is of serious concern, Europe's focus has tended to be on the air proximity and level-bust [altitude breaching] problem, on which far more data has been submitted.

Stastny says that part of the difficulty has been convincing national authorities to hand over the information. In its April 2001 Performance Review Commission report, Eurocontrol found that only 20 member states contributed safety-related occurrence data in 1999 - the latest year for which comprehensive figures were available. Stastny says this is not unusual, adding: "States treat safety data very much as a national issue. They might have a reporting system, but be reluctant to let the summaries go."

To improve matters Eurocontrol has been gathering information on ATM-related incidents, including runway incursions, since 1999 under a project linked with the development of a harmonised incident-reporting database - a project known as the Tool Kit for ATM Occurrence Investigation (TOKAI). "This had already given us some idea on the scale of the problem," says Jacques Beaufays, who heads the runway safety division within Eurocontrol's Safety, Quality Management and Standardisation unit. "It was a way of triggering wider data collection."

Having already ploughed through the existing data files of national airspace authorities to lay the foundation, the Eurocontrol task force put together a runway safety survey and distributed it via the mainstream aviation organisations: including the International Air Transport Association, the International Civil Aviation Organisation, the Joint Aviation Authorities, pilots' and air traffic controllers' unions and Airports Council International, in an attempt to analyse the factors which cause incursions. The task force will also make use of US Federal Aviation Administration data, including the agency's "severity matrix" for measuring the seriousness of incursion incidents, to provide data comparisons and establish whether the US agency's conclusions can be considered valid in a European context.

Initial survey results on occurrences in Europe covered almost 1,850 responses, nearly 95% of them from pilots. One-quarter of respondents claimed to have seen or been involved in a runway incursion in the previous two years - and 46% of those considered the potential for collision to have been big. The most prevalent contributory factors, they reported, were problems in radio phraseology and language proficiency, airport layout and guidance, and air traffic control procedures. More than half did not know whether their primary airport had a specific runway safety reporting scheme. Of the remainder, one-third stated that no such scheme existed.

Airport variation

Any task force recommendations, says Beaufays, will have their basis in ICAO rules. But he stresses that a key difficulty facing the task force is the variation between airports - strategic measures suitable for one location might make little difference at another. Instead of issuing a broad set of specific guidelines, Eurocontrol will have to address the problem by advising the adoption of a tailor-made safety-management approach. "Milan's accident has accelerated the [task force] timescale," says George Paulson, director of the Eurocontrol safety, airspace, airports and information services directorate. He is reluctant to pre-empt any analysis while data-collection work continues, but he says: "The responses are telling us that runway incursion is an issue in Europe."

Given the FAA's experience on the matter, there is intense interest in whether fundamental differences exist between US and European airports which, in turn, might provide an insight into the problem. Complexity of airport geometry is one element under examination. Intersecting runways are not as common in Europe as in the USA. Many of Europe's main hubs, such as London Heathrow, Frankfurt, Munich and Oslo Gardermoen conduct parallel runway operations, using dedicated departure and arrival runways. If these parallels are either side of the central terminal area, the need for aircraft to cross active runways is reduced.

Aéroports de Paris, which witnessed a fatal incursion at Paris Charles de Gaulle Airport in May 2000, has worked not only to reinforce the importance of correct language and phraseology, a contributory element to the accident, but also to improve runway-crossing procedures and the visibility of runway intersections after two serious incursions occurred within 2h of each other in November of the same year. In both cases, arriving aircraft crossed an active departure runway despite acknowledging instructions to stop.

Amsterdam Schiphol expects to open a fifth runway by early next year, increasing the number of taxiway/runway crossing points from 10 to as many as 16. Schiphol could theoretically see almost one runway crossing per aircraft movement. The airport is revising its air traffic control procedures to reduce the incursion potential generated by the increased complexity.

Aside from the obvious regulatory variations between individual countries, Europe also differs in other respects from the USA. To maximise landing capacity, several US airports operate the controversial "land and hold short" procedure - whereby landing aircraft are ordered to brake before reaching an active runway intersection. The practice is shunned in Europe.

Overall, airport traffic volumes in Europe are smaller than in the USA. Of the 50 airports in either region which have over 300,000 yearly aircraft movements, only about 20% are European.

Studies by Transport Canada have indicated that incursion events tend to increase rapidly with traffic volume - although the relationship between the two is complex - and have further shown that capacity-enhancing measures can be detrimental to incursion avoidance efforts.

General aviation

General aviation activity features heavily in US runway incursion incidents. Europe's lower levels of general aviation mean that such activity does not predominate in European runway safety incidents. In a survey of six European hubs - Amsterdam, Brussels, London Heathrow, Munich, Oslo, and Paris Charles de Gaulle - FAA runway safety analysts observed that all the airports had strong technological solutions in place, such as surface-movement radar and ICAO-compliant signs, and that they shared common training practices for airport vehicle drivers. The FAA's primary concern was the lack of a formal ATM occurrence-reporting system - a matter which the TOKAI programme is addressing.

But the strong feeling among the European air transport community is that there is no quick fix to the incursion threat. Although a number of specific improvements at certain airports, combined with the safety net available with modern technology, might eliminate the more obvious problem areas, the individual circumstances and scenarios which conspire to create incursions will almost certainly require in-depth site-specific reviews rather than general guidelines.

"It's quite difficult to identify what's causing it," says Beaufays. He argues that the general profile of the incursion problem in Europe is not vastly different from that in the USA, and believes that the key lies in understanding an element common to both regions - human error. "The fact that the problem is present in almost any airport shows that there is something inherent," he adds.

Source: Flight International