1.   INTRODUCTION

1.1           The use of electronic data displays in control towers is growing. In the United Kingdom it is intended that the four major London airports will soon all adopt a common electronic traffic data display in the form of electronic flight progress strips. Whilst the proposed system is Canadian, a number of similar European systems are available.

1.2           Existing IFATCA and Guild policy on automation is relevant and is reproduced in Attachment A.

1.3           Part of the existing Guild policy on computer assistance is relevant and is reproduced in Attachment B.

1.4           This paper considers the need for additional policy specific to the introduction of electronic displays at Airfields and particularly for use in Aerodrome control.

2. DISCUSSION

2.1       Strip design

2.1.1    Electronic displays for ATC fall into four broad categories or into hybrids of these four techniques.
            i           Simple electronic data displays;
            ii           Emulated paper strips;
            iii          Electronic strips;
            iv          Dynamic Electronic data reproduced within a graphical environment.

2.1.2        Simple electronic displays whilst good for manipulating tabular data are less effective when asked to indicate fluid graphical relationships between data fields, a routine requirement for aerodrome control.

2.1.3        Emulated paper strips have the advantage that their design, content and manipulation can be arranged to mirror the use of paper strips with benefits for conversion training. However the pure emulation of paper strips can deny controllers many of the potential benefit of electronics, and intended operational benefits therefore tend to dictate that emulation alone is inadequate.

2.1.4        The use of radar or situation displays as data displays is well established for surface movement guidance systems, but as yet little work has been done to develop that technology to provide aerodrome control with a total graphical environment.

2.2            Displays

2.2.1        Almost by definition aerodrome control is carried out in an environment where electronic displays are subject to more glare and reflection than in the closed environment of an operations room.

2.2.2        Additionally electronic strip displays may be positioned in a horizontal or near horizontal attitude.

2.2.3        At night the same displays must be equally effective when operating at reduced light levels.

2.2.4        Aerodrome control being a visual medium requires more mobility from a controller than do other roles. The controller’s proximity to the electronic displays and the range and angle at and through which the display can be read are more critical.

2.3       Controller interface

2.3.1        Flight progress strips capture, display and provide a record of data entries. Any electronic medium is required to do the same, but the technique may vary. Data entry and manipulation needs to be simple and to impose an insignificant task load.

2.3.2        Electronics used intelligently can help the controller. For example if the strip has fields for current time entries the strip system should already know the time, so all the controller would need to do is click the box, not type in the time. Any sequence of electronic processes routinely precipitated by that time entry ought then to be initiated without the need for any further controller action.  The confirmation that those operations had occurred should be automatically fed back to the controller (or perhaps the controller is only told if the sequence failed and where, so that corrective action can be taken).

2.4       Systems interoperability

2.4.1        Unless the aerodrome display links into the wider ATM system potential benefits will be lost. Data entered in a tower should not need to be re-entered again for that flight within the UK or European ATM system.

2.4.2        With the advent in the near future of traffic management tools to produce, for example, optimum departure and arrival sequences for whole terminal areas it is essential that all data available is known to the network of management tools.

3.         CONCLUSIONS

3.1              Emulated flight progress strips are likely to be the more efficient form of data presentation for a first generation system but the potential advantages of new electronic functions should not be totally neglected in order to simplify the introduction of electronic strips and controller training.

3.2              The sighting of displays of electronic flight progress strip displays is particularly sensitive.

3.3              Controllers should be able to expect that the functionality of the electronic strips matches the task required of them, that no increase in overall workload should be experienced, and that wherever possible reductions in workload per aircraft should be obtained. 

3.4              Electronic strips used at Airports should be capable of supporting electronic data transfer with the European ATM system.

4.         RECOMMENDATIONS

4.1              Elements of existing policy already cover the eventualities described in 3.1, 3.2, 3.3.

4.2              It is recommended that electronic flight progress strip systems used in control towers shall be capable of interface with the wider UK and/or European ATM network.

ATTACHMENT A

Policy on Automation

GATCO

·        This Guild is not opposed in principle to the introduction of automation in the form of controller tools, decision support tools, automated tools and assistance. However in order to protect controllers it believes that the introduction of such systems has wider implications than just the technical issues and that a wider debate on the proposed introduction is required.

·        The proposed introduction of controller tools, decision support tools, automated tools and assistance requires in each case a formal operational, human factors and regulatory review of the impact on the future role and responsibility of controllers.

·        The review should consider in particular:

The potential degradation of the controller’s dynamic traffic model "the picture" and the impact of any such degradation on the ability of a controller to honour existing responsibilities.

The potential for controllers to become reliant on the tools and the consequences of that.

The controller’s ability to safely contribute at all to continuing service provision in the event of a catastrophic system failure at peak periods.

IFATCA

Automation must improve and enhance the data exchange for controllers. Automated systems must be fail-safe and provide accurate and incorruptible data. These systems must be built with an integrity factor to review and crosscheck the information being received.

The Human Factors aspects of Automation must be fully considered when developing automated systems.

Automation must assist and support ATCOs in the execution of their duties.

The controller must remain the key element of the ATC system.

Total workload should not be increased without proof that the combined automated/human systems can operate safely at the levels of workload predicted, and to be able to satisfactorily manage normal and abnormal occurrences.

Automated tools or systems, that support the control function, must enable the controller to retain complete control of the control task in such a way so as to enable the controller to support timely interventions when situations occur that are outside the normal compass of the system design, or when abnormal situations occur which require non-compliance or variation to normal procedures.

Automation should be designed to enhance controller job satisfaction.

The legal aspects of a controller's responsibilities must be clearly identified when working with automated systems .

A Controller shall not be held liable for incidents that may occur due to the use of inaccurate data if he is unable to check the integrity of the information received.

A Controller shall not be held liable for incidents in which a loss of separation occurs due to a resolution advisory issued by an automated system."

Attachment B Policy on Computer Assistance

It is recommended that Controllers who will be using tools that will interface directly with that controller’s skills and technique shall validate without the use of the tools. 

Additional continuation training shall be provided to enable controllers to practice manual control techniques with live and/or simulated traffic to maintain their skills levels. 

Work shall be carried out to establish under what circumstances controllers are no longer able to control peak traffic without the tools, or can do so only by dispensing with the independent verification of the tools’ solutions.

When controllers can no longer control peak traffic without the tools, or can do so only by dispensing with the independent verification of the tools solutions, then the criticality of the software shall be upgrading as its function will have become safety critical and the tools a form of automation rather than computer assistance.

   Click here to return to Policy Papers Main Page