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

aircraft-to-aircraft separation responsibility can be delegated to the pilots concerned).
Controllers assess how all the aircraft are flowing through a sector or area of
responsibility, working out where adding structure (perhaps in the form of temporary
restrictions) will reduce the incidence of conflicts. When conflicts do occur, there is a
balancing of the needs of the individual aircraft and an attempt to confine the side effects
of any resolution maneuver to as few aircraft as possible. The controller, in any conflict
resolution strategy, balances the demands of each aircraft against the needs of all the
aircraft that are implicated. As discussed in Section 4.3.2, controllers impose structure
during dense traffic scenarios in order to reduce the incidence of conflicts. This is a
stabilizing and throughput maximizing strategy. The controller acts as arbiter where there
is a conflict of interest, but does not have time to discuss the resolution strategy.
Is it possible to transfer separation assurance to the pilots in the terminal area to achieve
VMC-type separation distances in instrument meteorological conditions (IMC) and
thereby increase runway utilization
The terminal area encompasses the most demanding phases of flight for pilots: approach
and departure. Taking on the additional role of separation assurance would have the
potential of considerably increasing that workload in IMC. In the event of any on-board
difficulty, pilot workload would rise, probably necessitating a reduction of overall tasks.
It is also probable that in order to achieve the goal of safe and stable flight the first task to
be off-loaded would be the separation assurance task. The transfer of such a responsibility
back to the controller would have to be explicit in order for each party to be aware of the
extent of changes in his/her responsibility. Such a sudden transfer at a time of already high
pilot workload could also lead to a situation of higher than acceptable risk. The aircraft is
already experiencing difficulty, and the intent information required as input to any decision
support system may be rapidly changing without either the system or the controller being
aware of the extent of these changes. In additional, separation standards associated with
airborne separation assurance concepts might be less than those which an unsupported
controller could sustain. Thus the controller is presented with a situation where the
appropriate separation does not exist for ground-based separation. In this context, the
system is potentially fail-dangerous.
By going through this type of failure mode analysis, it is clear that if separation assurance
is shared with the flight deck in order to achieve reduced separation standards, then
adequate redundancy must be provided to prevent the immediate reversion to control by
an unsupported controller on the ground. This points to a need for consideration of some
critical human factors issues on the flight deck, not the least of which is a major potential
shift in pilot roles, tasks and operating procedures. There seems little likelihood that pilots
will be able to support aircraft-based separation in potentially high workload scenarios
without the integration into the cockpit of major decision support systems. In such a
scenario human factors issues which are raised, both in the cockpit and at the controller’s
workstation, should be examined without delay.
The other issue connected with the sharing of responsibility is that of ensuring that actions
chosen by pilots as resolution strategies do not cause other conflicts. There is a need to
constrain the possible range of strategies commensurate with traffic conditions.
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