38TH ANNUAL CONFERENCE, Santiago, Chile, 15-19 March 1999
WP No. 154
Transfer of Separation Functions to Pilots – Human Factors Aspects
The subject “Transfer of Control Functions to Pilots” became part of SC4’s working programme at the Toulouse conference 1998.
SC1 has already done a great deal of work on the technical aspects of control transfer. This by necessity includes some human factor issues. SC4 has attempted to address the issue more from a conceptual point of view. By this we mean we have accepted that the concept may become a technical reality, but is it necessary and will it achieve any worthwhile objectives.
ATM strategy for Europe (ATM 2000+) inter alia states, that “the limited transfer of responsibility for separation from the ground system to the cockpit will lead to a reduction in the ATC workload, associated with routine monitoring, conflict search and problem solving tasks”.
One important point to realise is what “transfer of control” means exactly. It is not just an instruction such as climb to a certain level or to turn onto a certain heading while maintaining separation with another aircraft. It is exactly what the words say, transfer of air traffic control to the cockpit, although this does not necessarily mean the pilot!
By transferring control functions to the cockpit, the pilot’s workload will increase. The pilots themselves and some expert institutions have questioned the advisability of this. (Future of Air Traffic Control – Locus of Authority Recommendations 1 & 2) Not only is the separation function transferred to the cockpit but also the responsibility. It has to be investigated to what extent that can be done without affecting aircraft safety.
If the aim of the transfer of control is to increase capacity then a most important consideration is that the responsibility for the separation function cannot simply be handed back to the controller when flight deck workload no longer permits aircrew to undertake this function. Almost by definition the moment this occurs, the controller will be instantly overloaded. If this is not to be the case then capacity must be kept within controller capability. If this is a requirement then it defeats the purpose of the transfer of control?
Controller skills are maintained by continuous practise and exposure to different circumstances, building an experience base within which to exercise the skills. This degrades rapidly when not continuously used, as any supervisor will tell you. If the controller becomes a system monitor then it is arguable that our skills will degrade in the same way that it is argued that pilot skills have degraded with the introduction of computerised flight management systems.
The ATM 2000+ document aims in 2.2 can be achieved by a greater concentration on ATC hard and software. This technology could then accommodate all aircraft; not solely those equipped for EFR. (Electronic Flight Rules). A Eurocontrol study (Deep Design – Beyond The Interface) identified that tasks particularly suited to humans are:
a) Conflict resolution (but not detection);
b) Dealing with special requests from pilots;
c) Rectifying errors detected by computers;
d) Imposing strategic direction over a system;
e) Applying conventions to reduce workload
A reorganisation of controller responsibilities to remove the time consuming detection and coordination tasks may well produce the same result without denying the use of airspace to non EFR equipped aircraft.
It has yet to be shown that transfer of control can achieve the objectives of the aviation industry except perhaps in areas of low traffic density and little ATC capability where, like ACAS, it has the potential to enhance safety. However, like ACAS, all aircraft in the airspace need to be equipped to achieve the objective.
If separation functions are transferred to the cockpit the situation awareness and skills base of the ATCO will be degraded to the point when intervention will not be possible.
Aircrew workload will increase by fulfilling additional tasks, which are currently carried out by ATC. This might lead to overload situations in cockpit workload when other, higher priority, tasks have to be taken care of by the crew. Responsibility for the control function cannot simply be handed back to the controller.
The aims of the aviation industry may be better met by enhancing the controller separation capability.
It is recommended to conference that the following Provisional Policy Material be adopted:
From a Human Factors aspect IFATCA has strong concerns over the transfer of control responsibility to the cockpit for the following reasons:
- If separation functions are transferred to the cockpit the situation awareness and skills base of the ATCO will be degraded to the point when intervention will not be possible, and
- Aircrew workload will increase by fulfilling additional tasks, which are currently carried out by ATC. This might lead to overload situations in cockpit workload when other, higher priority, tasks have to be taken care of by the crew.
- Responsibility for the control function cannot simply be handed back to the controller.
Free Flight and the Pilot, By: Captain Peter M. Foreman, as presented at SMi: Air Traffic Management II, Prospects for Free Flight Conference, 14 January, 1998: Marble Arch Marriott Hotel, London.
The Future of Air Traffic Control – Human Factors and Automation, University of Illinois.
Deep Design – Beyond the Interface – Hugh David, Eurocontrol Experimental Centre.
Last Update: September 28, 2020