Whose sky is it?

New technology for air traffic control blurs the lines between the traditional jobs of pilots and air traffic controllers, says Fredrik Barchéus at the Royal Institute of Technology (KTH) in Stockholm, Sweden.

International civil aviation has experienced a steady growth in past decades, which is predicted to continue and, to overcome capacity limits of the old Air Traffic Control systems, new technologies are being developed.

While current air traffic control systems have evolved continuously, the new technologies are part of a new paradigm that has the potential to completely reform aviation. Under the new system it is envisaged that pilots may carry out surveillance tasks, which will pose new demands on coordination between controllers and pilots.

Recognising that the current Air Traffic Control system was insufficient to cope with the projected demand, a plethora of research initiatives have emerged. Institutions as diverse as governmental agencies, professional interest groups, airline companies, air navigation service providers, universities, research institutes, and equipment and airframe manufacturers have all embarked on a joint venture to create and implement the new system.

The thinking behind this development is that the current air traffic system is too focused on reactive measures on a tactical scale and that this results in a sub-optimised flow management. To overcome this, the main thrust of the new development concentrates on Air Traffic Management (ATM), as opposed to Air Traffic Control (ATC). This requires that the future ATM be designed around the three basic pillars of aviation: Communication, Navigation and Surveillance and is called CNS/ATM.

New technology

New technologies such as satellite navigation, data link communication, and ADS-B (aircraft send out information about their position) have the potential to totally reform aviation routines by making it possible for the same system to run both navigation and monitoring. These tasks have traditionally been divided between pilots and air traffic controllers.

The present division of jobs between the pilot and the air traffic controller is mainly based on the historical development and application of technological equipment - above all radar technology. The new technology allows information in the aviation system to be shared to a much greater extent. For example, air traffic controllers can gain greater insight into navigation in certain phases, while pilots can be responsible for staying out of the way of other aircraft.

Inside insight

To gain wide insight into current aviation, a multitude of data-collection methods have been applied including interviews, observations, and simulations performed with both pilots and controllers from several European countries. Observations have been performed in operational Air Traffic Control as well as operational flight. Observations have also been performed in simulations where some applications of the new technology have been investigated.

Results show that operational activity is characterised by a large degree of flexibility. In some applications of new technology, certain tools and procedures have been identified that have been regarded inflexible. Though there must be strict procedures to ensure safe operations, too rigid procedures may also hamper operators' use of creativity and competence, and may in some cases constitute obstacles to the overall goal of efficient and safe operations.

The interviews with air traffic controllers from several European countries have shown that there is some concern about the future in terms of where the responsibility will lie in various situations, and how it can be transferred safely.

Appropriate procedures

New technology forces us to develop appropriate procedures to allow us to continue to fly safely. One key aspect is how the exchange of information should take place between air traffic controllers and pilots. Both data link and radio are possible modes, or even a combination of both.

Observations from simulations in which the new technology was tested by pilots and air traffic controllers show both pros and cons for both communication modes. Transferring numbers via data link reduces the risk of misunderstanding in one way, while radio communication allows the air traffic controller to tell from the pilot's tone of voice whether he understood an instruction. If not, the instruction can be repeated in a different way.

The technology already exists and can be implemented as soon as airlines and civil aviation authorities are ready to make the change. However, there is stiff competition in the air travel market and airlines do not have the capital to invest in new technology. But down the road the authorities are going to want to replace various national systems with a common European set-up under the motto 'A Single European Sky'.

Regardless of when the change happens, it's important that it's done using international collaboration and for developers to place great emphasis on human factors such as procedures, phraseology, and training of pilots and air traffic controllers when the technology is introduced.

Future research

It is generally acknowledged in the aviation community that any future developments should be carried out internationally, and projects such as Mediterranean Free Flight, ASAS-Thematic Network, and Human Integration into the Life cycle of Aviation Systems, are examples of such cooperation.
One suggestion for further research is to investigate the opportunity to exploit different time scales as a base for role allocation. Since pilots may engage in separation work to a greater extent with use of new technology, controllers may focus on planning and flow management. Controllers could perform trajectory changes for direct implementation in the aircraft. Provided that the change is sufficiently far ahead in the future, this would not constitute a major issue for the pilots and could be performed on a very high automation level, i.e. the pilots would only have to know the change if explicitly requesting the information.

Further, recognising that time-based separation may be more reasonable than distance-based separation, it makes little sense to display positional information to human operators. Current flow management tools may depict time-based relations between aircraft as spatial relations. In these cases, the aircraft are planned for the same destination. It would be interesting to expand the scope of time-based displays to the three-dimensional case.

Lack of technology

The present separation of tasks between pilots and controllers is caused by a historical lack of appropriate technology. The introduction of new technology may solve this, but since clear roles have been established between controllers and pilots, a redistribution of tasks may be compared to introduction of automation.

To achieve successful implementation of new concepts, it is acknowledged that it should be done gradually while coordination with affected areas, geographical as well as organisational, should be retained. This should limit the impact of each of the tools than if large batches of tools were implemented at once. This would then leave sufficient time for training and adaptation.

However, a consequence of this is also that training will have to be extended for a long period of time, and may thus add to the cost. Training needs could be mitigated by the use of similar working procedures for different applications, but as many parts are intended for the flight deck, it also becomes a matter of who will bear the cost.

The technology described here is currently reaching sufficient maturity and initial implementation is underway. Despite a large interest from several parties, the main question of investment capital largely remains. With the new technology, the airborne side of aviation can take a larger portion of responsibility, but this is dependent on hardware investment on the aircraft.

Airlines have been under severe financial stress for some time and may be reluctant to engage in investment programs that do not produce a quick return on investment. The main issue from a development perspective is thus to identify applications that can be linked to revenue for the airlines, and airlines willing to engage in early trials.

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