David Learmount/BRUSSELS
THERE IS A BALANCE to be struck in air-traffic-control (ATC) provision for the future: the balance between the capabilities of advancing technology and the fact that ATC will involve a significant human input for the foreseeable future.
New-technology ATC equipment for use in and around Eurocontrol's 17 member nations will be provided by different manufacturers to sites in many countries. The minimum technical requirement is that it does its specified job and can harmonise and communicate with equipment in the increasing number of European countries, which are gathering under Eurocontrol's co-ordinating umbrella.
There is, however, a supra-technical requirement - the most demanding specification of all. Eurocontrol's head of human resources, Chris Clark, explains: "As far as it is possible to see into the future, air-traffic controllers will sit at workstations and play an executive - not just a monitoring - role."
Despite an inevitable increase in the level of automation, Clark says, ATC equipment will, nevertheless, have to be designed to keep the controller "in the loop". Dr Manfred Barbarino, chairman of Eurocontrol's Job Description Task Force (JDTF) in Clark's Human Resources Team, explains that it is vital to determine, which tasks should be carried out by people and which, by using automated systems rather than automating as far as possible and leaving the controller to cope with whatever tasks remain.
In due course, because of advanced ATC human-factors research recently begun, Barbarino believes that, more will be understood about the "cognitive" side of the ATCO's task, so the effect of introducing a new piece of equipment will be more predictable.
Clark's concern is for the future. Today's displays and workstations, gradually improved to give controllers more access to information - and particularly, on the latest displays, to better predictive information - still leave the controller with full executive authority. Controllers' decisions and actions are based completely on the tactical traffic "picture" of a dynamic situation, presented visually and by voice, which they build up in their own brain.
An impressive example of how today's controllers - kept in the loop by using traditional equipment - occurred on three occasions in the last 15 years when there was a total mains power-failure to the London Air Traffic Control Centre (LATCC), which controls almost all the UK's airspace. Using limited displays operating on battery only, but having a clear mental picture of the traffic they were handling, the controllers stopped aircraft taking-off or entering the area and calmly processed the traffic under their control, until the skies were emptied to the level at which they could be handled procedurally.
Luckily, in each case, the power was restored in less than 1h. In Ireland in September, Dublin's control centre experienced a catastrophic lightning strike, which knocked out all screens except remote displays relayed from Shannon, which did not show low-level traffic. Dublin Airport's ILS was also completely disabled, leaving only the VOR navigation beacon to aid procedural let downs. The controllers, being fully "in the loop", proceeded as LATCC had done, and succeeded in maintaining safe aircraft separation.
The future will demand more than this, however. Air-traffic movements in already-crowded airspace need to be able to double within 20 years if demand is to be met. ATC systems have to increase their capacity, using a combination of redesigned air routings, new-technology equipment, international ATC integration (Eurocontrol's task) for greater ATM efficiency, and, finally, more effective man-machine interface. Each piece of equipment and all traffic patterns have to be designed to enable the controllers, still in an executive role, to cope safely with the increased demands.
One of today's controller's best-established tools, the hand-manipulated block with a paper flight progress strip (FPS) on it, is threatened despite much protest from the traditionalists. A simplified printout of the basic detail from each aircraft's flight plan, each FPS is updated in the controller's own handwriting as he issues instructions or clearances to the aircraft in question. It has many qualities, which the human factors (HF) specialists applaud, like its physical/psychological representation of the aircraft, its personal nature as the controller writes on it, the speed and economy of effort with which, entries can be written (compared with keyboarding) and the memory-enhancing function of making the entry.
Ron Longley, business area manager for LATCC work at the UK National Air Traffic Control Services' (NATS) Air Traffic Control Evaluation Unit (ATCEU), emphasises another benefit of the paper FPS: "It's beauty is that it can't 'crash' [fail] when the display does." Having the FPSs in front of them helped the LATCC controllers when the power failed by providing a record of all the aircraft under their individual responsibility, and of all the recent transactions with the aircrew.
Langley explains the FPS's weaknesses, however: "What's written on it can be seen usually by only two people, and by a maximum of three under normal circumstances." He describes a planned "stripless" environment - the UK's New En-Route Control Centre (NERC) - to become operational in 1996: there, he says, by updating electronic FPSs, which are shown on a display at the workstation, the controller has the same record, but anyone else who needs the information can access or observe it. What is more, points out Langley, the need for controllers to pass the data to each other by telephone on handovers is also eliminated, saving time. The continuing task is to shorten the keying-in process for the electronic FPS, and to ensure systems backup which leaves the FPS information available if the main system crashes.
Clark's team is working at defining the precise role of tomorrow's controller, reflecting the evolution of the European Air Traffic Control Harmonisation and Integration Programme (EATCHIP) evolves. He explains: ""We're having to do the abstract work, but the purpose is purely practical. The whole of EATCHIP is a change. We're trying to enable that change to take place."
Implicit in EATCHIP is the need for controllers to work with new-technology equipment and to operate as part of a much larger, fully coordinated air traffic management (ATM) organisation than they have done in the past. Despite overtures by his department to the major workstation-equipment suppliers, however, Clark says that there is "almost no contact" with them.
"We will have an effect on how equipment is used, rather than what equipment is used, although entry into the design process is, in my opinion, very important," Clark remarks. He adds: "We have to have a very clear description of what we want to do - which is what we are defining now. We have gone from procedural control to automatic without changing the fundamental approach to the task. The people we select have got to be able to cope with what we do in the future. People today have been selected and trained only for what we do today."
Eurocontrol's overall human-resources job is to draw up a European "operating manual", to define ATC procedures and standards to which all the Eurocontrol member nations will adhere. Barbarino points out that, within Europe today, national definitions of controllers' jobs vary, the social status of ATC work varies and so do pay and conditions.
Without this job-definition research, EATCHIP could not have a unified human-factors base - it would consist merely of technical harmonisation and an improved communications infrastructure between sector air-traffic-control centres (ATCCs). Ultimately, says Clark, there will be a Eurocontrol ATCO licence, just as there are (or soon will be) European Joint Aviation Authority licences for aircrew and maintenance engineers.
In drawing up the new standards, says Clark, it is not enough to analyse what a "controller" does today and extrapolate from that model. ATCCs of the future will use controllers differently because of changed ATM methods in a different environment.
Controllers, for example, will monitor airspace sectors using automatic dependent surveillance (ADS) as well as (or instead of) primary and secondary radar; use datalinks instead of speech for most communication; and will have to maintain separation between aircraft, which are cleared for en route "free flight" (also known as area navigation or direct routeing), rather than being restricted to airways.
As a result of the changed demands, it may be necessary for ATC teams at future regional ATCCs to be structured completely differently from those at today's ATCCs. As Clark says: "We have to be two or three steps ahead of the game and try and stay there."
HUMAN FACTORS NOW
While the JDTF completes its research, more immediate work on promoting the application of ATC human-factors techniques is being carried out by the EATCHIP Human Factors Team's short-term benefits task force (STBTF), which has just produced its first draft paper. When the paper is completed it will provide ATS managers with guidelines on how to identify areas in their organisation which could benefit from new human-factors techniques.
Just as aircrews have had the crew-resource management principle as part of their training for many years, Clark points out, that similar principles are being employed in what he calls team-resource management for ATC. This, Clark explains, at present only encourages ATS organisations to hone their teamwork skills among themselves but, he predicts, "...will intermesh the pilot's and controller's roles more closely".
SYSTEMS EVALUATION
The UK NATS, provider of ATS for the whole of UK airspace, has its evaluation unit (ATCEU) at Hurn Airport in southern England. The unit's name is descriptive of its job as a practical tester of new ATC equipment, systems and procedures before they go into operational service.
The fact that the ATCEU's name is about to change for more than cosmetic or administrative reasons reveals that it will have a much larger and more human-factors-centred remit: the name for the new unit - not yet finally decided - will probably be the Air Traffic Management Development Centre (ATMDC).
Ron Longley, of the ATCEU, explains today's task: "We are presented with a range of equipment and whole systems, and [our job is] a mix of influencing system design and making existing systems work." That job, however, is evolving, Longley explains: "We are getting closer to the point where we can approach NATS at the beginning of a programme and work from there."
Nic Turley, senior scientist at the ATCEU, says: "We have been in the human-factors game for a long time, but very focussed. Our efforts have been on the evaluation of specific tasks." The ATCEU has not had the luxury, like Eurocontrol, of writing the human factors specifications and designing a future system around them.
The ATCEU's senior psychologist Alison Evans observes that there has been a natural progress towards making more use of human-factors research techniques, remarking: "When we first came here there was not an efficient relationship between human-factors staff and the organisation. This is changing rapidly." She says that human-factors awareness, now part of ATCO training, has had its visible effects from her perspective, observing: "Controllers have been more and more keen to become involved in human-factors design analysis, to the point where they would kick up a fuss if we did not consult them."
Now the ATCEU confirms its new human-factors terms of reference: "To date, work has been focused on the latter stages of a project lifecycle. The establishment of a human-factors unit (HFU) at the ATMDC will involve human-factors specialists throughout the project lifecycle." The HFU will have an extensive remit:
to be a central focus in research and development for human factors matters;
to be a source of human-factors expertise throughout NATS;
to produce and maintain guidelines and standards for human factors in NATS, particularly for specifying and conducting projects.
ATC MISTAKES
ATC incidents have always been recognised as a potential source of information on ATS weaknesses, but the investigation teams have not, until relatively recently, included human-factors specialists as a matter of course. Dr Sue Baker of the UK Civil Aviation Authority Medical Division's human-factors psychology group reveals that incident reports are now to contain a psychological report where appropriate. Baker emphasises: "There's no hidden agenda. We ensure that controllers know that human factors is the aim."
On the question of whether a human-factors study can yield ATC system results, Baker quotes the results of the study she wrote following an incident involving a British Airways British Aerospace One-Eleven. The incident, on 10 June 1990, did not involve an air-miss or even a direct ATC error, but nevertheless the report criticised ATC for its failure to enable the co-pilot to achieve the quickest possible diversion in an emergency.
The main windscreen panel on the pilot's side had blown out at 17,000ft (5,200m), and the captain, who was almost sucked out by the pressurisation differential, would have been lost had a steward not grabbed his legs and held them until after landing. The captain survived, despite injury and frostbite.
The need for quick recovery was clear, but the LATCC-based controller, unaccustomed to emergencies because of their rarity, offered the beleaguered co-pilot in his chaotic, noisy cockpit, choices of what to do, rather than recognising the pilot's need to be given radar-vectors to the nearest possible safe landing place. Radar vectors to Southampton were soon given after the pilot had requested them, but the stricken aircraft's time to landing could have been reduced by several minutes at a time when seconds were important.
Baker's report on ATC action in the incident highlighted the clear need for recurrent emergency training, a measure which was immediately implemented. She comments: "I was particularly pleased by the introduction of emergencies training, because it is such a practical skill, and practical skills have to be reinforced by refresher training. Most of a controller's skills are reinforced on the job, and those which are not need regular practice."
Baker describes her job as being involved in studies from ATC tower ergonomics to "generics, like training", but disclaims any major breakthroughs. Her job is to look for ways to improve the system she says, observing: "If there was a gaping hole in the system something really nasty would have happened already."
Baker's department comments that causal and contributory factors to serious ATC incidents in UK airspace are "extremely diverse", but that they are frequently related to "the reliance which needs to be placed on a human operator in what is a very complex system". In other words, human beings can be expected, occasionally, to make errors when they are under the pressures to which today's system subjects them. Tomorrow's system, therefore, expected to be able to process far more traffic, has to be different, and the HF experts are trying to work out how that can be done.
US HARMONY
Eurocontrol's Barbarino acknowledges that the USA pioneered the early studies of human factors in ATC, which may explain why the agency's work on concepts such as CRM/TRM seems to harmonise with existing US programmes. Mark Hofmann, manager of the human-factors division of the Federal Aviation Administration's office of aviation research, says that ATC human-factors research continues in several areas: NASA Ames is studying equipment "to aid controller decision-making" - Hofmann supports Eurocontrol's contention that hardware and software should be created to support the controller, not vice-versa.
Another study the FAA highlights as particularly important, in parallel with that being conducted for aircrew, is on work/rest cycles. An important objective is to define clues, which will enable controllers and supervisors to identify the onset of real fatigue.
Australian Bureau of Air Safety Investigation (BASI) director Dr Rob Lee says: "Many ATS incidents [can] reveal latent failures within the ATS [air-traffic services] system. Its vulnerability to both human and technical failure is perhaps most clearly revealed through air-miss occurrences."
In the six months to mid-May this year, 47 reported instances of "separation breakdown" occurred between two or more scheduled aircraft in Australian controlled airspace. In the same period there were 168 incidents involving a scheduled and a non-scheduled aircraft. In ten of the events, traffic-alert and collision-avoidance systems (TCAS) on aircraft were credited with a positive role at least in resolving a conflict. Australian domestic aircraft are not yet required to carry TCAS.
In its Australian Air-miss Study, BASI has adopted a case-study approach to human factors in Australian ATC operations, to analyse the ATM system's weaknesses. The study observes that improvement may be achieved by reducing "violations, errors, psychological precursors of unsafe acts, and organisational deficiencies".
BASI defines the causal categories as:
violations: deviations from standard operating practices, including routine shortcuts; activity which does not give safety the highest priority; or exceptional behaviour dictated by unusual circumstances;
psychological precursors of unsafe acts: these include workload, organisational deficiencies, events in the individual's private life, intra-organisational tensions, group norms condoning violations;
organisational deficiencies: these include inadequate strategic planning for ATM and for training, lack of attention to the "organisational climate", and poor quality assurance.
BASI observes: "The incidence of violations can be most effectively reduced by changing those organisational factors which most directly affect particular local factors, such as attitudes, group norms and morale; [like] training, workplace- and task-design, time pressures and environmental elements such as lighting and noise."
Among the organisational deficiencies identified by an independent consultancy were inadequate ATS quality assurance, lack of documentation and staff training in the operation of a revised "two-tier" safety regulation and surveillance scheme; and little formal accountability for safety at a managerial level.
Under the predisposing psychological factors heading, BASI identified a lack of team resource management, and criticised "excessive self-reliance" in some individual controllers. Other individual human factors included:
focus on tactical, rather than strategic control;
an excess of anticipation;
workload: both excessive and minimal levels create problems;
acceptance of frequent distractions in the work environment;
ambiguity in the service provision/safety priority balance;
working around system deficiencies;
uncertainty about personal career.
Aircrew have a role in ATM also, which BASI says is not emphasised or understood in training, explaining: "Aircrew seem to be unwilling to scrutinise controllers' actions. Thus the vital part that pilots can play in detecting error is under-utilised."
THE UNKNOWN
The future could evoke nightmare images of a controller's display covered with returns wheeling like a flock of seagulls over a rubbish tip. The UK ATCEU's Longley, however, predicts that the future skies of the future, with potentially controller-confusing concepts such as en route free flight, will not be quite the free-for-all that seems to threaten, with its need for absolute dependence on automatic control to ensure separation in congested areas. Outside congested areas of course, free flight is often cleared today except in areas which can only be controlled by procedural means.
Longley points out that, in the congested areas, ATM procedures and patterns are already being designed to be "less tactical - traffic is streamed to have fewer conflict points". In congested areas such as Europe, which has a large number of major hubs, crews calling for direct routing will tend to create the busiest streams between the major airports.
In the end, however, just how much freedom aircraft will be given depends entirely on the ability to analyse and understand what the human capacities of ATCOs are.
Source: Flight International
