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

• The highly peaked nature of air traffic demand, caused by passenger desired
travel times and airline hubbing operations
• The diversity of aircraft performance capabilities
• Competing objectives among system stakeholders
The primary safety objective of air traffic management is to assure safe separation between
aircraft (and ground vehicles) on the airport surface and in the airspace. The system
efficiency objective is to minimize the cost of operating flights through the system, both
under normal conditions, and in the face of disruptions due to weather or other causes.
3.1.1 Capacity and Safety
The capacity of the air traffic management system is fundamentally bounded by the
separation standards in effect for the airspace. Thompson (1997) reviews the history of the
development of airspace separation standards and states that the standards for radar
controlled airspace have evolved slowly and are not based on a formal model of collision
risk. By contrast, the separation standards in MNPS airspace in the North Atlantic were
developed through use of a collision risk model developed by Reich (1966). Reich’s
model takes into account only the aircraft’s guidance and navigation error characteristics,
due to the absence of air traffic surveillance in oceanic airspace. The model includes a
parameter that defines collision risk, and the use of the model involves a decision to accept
a certain value for this risk parameter.
System capacity, and therefore throughput, are bound up in the definition of separation
standards, and thus to accommodate the demand for growth in the NAS through 2015 it is
fundamentally important that a rational approach to separation standards development be
put in place. Risk management is at the heart of this process, which must find an
acceptable balance between collision risk and airspace throughput through a clear
definition of a collision risk parameter for controlled airspace.
The process of establishing separation standards must include a model of the nominal
system performance, along with failure modes and effects, all of which combine to provide
a certain probability of spatial overlap of pairs of aircraft. The factors that contribute to
the performance of the separation assurance function are discussed in more detail in
Section 3.2.6.
3.1.2 Throughput and Efficiency
It is important to consider the relationship between throughput and efficiency in the
current system. There is a need on part of system users to retain a certain level of
flexibility in routing to achieve an efficient operation. But, when considering that current
separation assurance methods are fundamentally based on a controller’s highly tuned
knowledge of a sector and its fixed path geometry, it becomes apparent that flexibility
could have a negative impact on airspace throughput. In addition, a controller handles
more aircraft by assuming that pilots stick to their assigned trajectories with a high
probability.
27