Air Traffic Management Concept Baseline Definition - The Boeing ...

3. It can consist of predetermined actions based on group or individual experience and
not published anywhere, and can be as extreme as stopping all departures from a
particular airport if a sector becomes dangerously overloaded.
There are major differences in the controller’s cognitive workload between allowing
aircraft to fly in a non-airways system, searching for conflicts as the traffic levels grow,
using novel strategies for each situation, versus that of enforcing structure and limiting
conflicts to particular, well-defined points where pre-determined strategies can be utilized
to resolve them.
The current strategy for reducing the cognitive workload on controllers when predicting
conflicts is to restrict traffic to conform to a particular structure. In this way, the cognitive
load per aircraft can be reduced so that the overall level (resulting from the total traffic)
remains at a manageable level.
The degree of detail on each aircraft’s passage through a domain of responsibility, which
the controller must retain, can be reduced using this structuring technique. If all aircraft
are on individual routes and profiles, then the removal of all structure and constraints from
the ATC system may well reduce the actual incidence of conflicts. However, although the
incidence of actual conflict may be reduced, there would probably be an increase in the
controller’s cognitive load because of the demand for more detail on each individual flight
in order to detect potential conflicts.
It is important to keep in mind that the primary role of the controller is to detect and
resolve potential conflicts, before they become actual conflicts. The act of tactical planning
and its constant revision reflect this responsibility. (See Section 6.4 for a discussion on
how to reduce the workload of searching for potential conflicts).
This issue is most obvious in terminal airspace where, due to the uncertainty of aircraft
performance in the vertical plane and the lack of good quality intent information currently
available, there are many more potential conflicts than for aircraft in a more stable cruise
environment. This aspect of detecting potential conflicts and understanding the heuristics
for determining what is a potential conflict are important aspects when establishing fast
time simulations to forecast the effects of different airspace organizations. It is the
potential conflict that creates workload for the controller, and in any situation where
aircraft are climbing and/or descending towards each other there is a need to manage the
uncertainty of these potential conflicts by close monitoring and probably positive
intervention until the situation becomes certain.
How controllers assess and manage uncertainty needs to be clearly understood before
schemes that involve removal or modification of some of the structures used to manage
uncertainty are implemented. Human factors knowledge needs to be used in determining
the impact of airspace structure on capacity, and the requirements for support for the
controller’s cognitive workload in a system that has less structure than at present.
4.3.4 Sharing Responsibility
Responsibility for separation assurance is usually vested in the controller except for very
specific situations (i.e. during visual meteorological conditions (VMC) when limited
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