Trajectory-Based Operations (TBO) - Joint Planning and ...

Trajectory-Based Operations (TBO)
Study Team Report
restrictions on demand earlier as conditions improve. What TBO does is provide the choices in
strategically managing demand.
The NextGen ConOps, built on TBO, requires automation to manage separation, spacing, sequencing,
and related relationships between aircraft. By 2025, the traffic volume will exceed what ATC can
safely manage by stepping in and assuming responsibility for separation for all aircraft. The basis of
control by exception is built on a few, not all. The expectation is that the controller will only need to
handle a small sub-set of the population of flights, not every aircraft. This means that TBO must
remain functional during off-nominal operations, both for strategic and tactical situations. As such, the
amount of demand that must be regulated is less than would be required in today’s NAS. Throttling
back demand is more surgical, impacting only those flights needed to sustain a pre-defined throughput.
This says that TBO must have a learning component that can set this pre-defined throughput based on
the demand, capacity, and the off-nominal condition. By continually refining the mitigation choices,
the NextGen system learns from prior experiences.
TBO choices first appear in options for flight planning. Flow contingencies are developed and shared.
Users of the airspace also offer their priorities that can be mapped to the options. “What if” scenarios
can be run for expected off nominal events. Once airborne, the choices are limited to what the aircraft
is capable of doing, based on information contained in the flight object. The ANSP TBO evaluation
service should not return choices that the aircraft cannot perform. When the controller receives options
for dealing with off-nominal situations, the controller needs the ability to tailor the query. Likewise,
the ANSP TBO evaluation service must be able to produce the plan used in shared situational
awareness. The plan must be tailored with the amount of time to go before the event actually happens.
An early version of the plan is available for flight planning. More refined versions emerge as more
information becomes available.
This plan must be scored against a common set of metrics. Post analysis tells how well the plan
worked, what the delay impact was, and where the delays were taken. It is the open, transparent nature
of post analysis that refines the ANSP TBO evaluation process—separating aircraft from each other
and the off-nominal conditions based on where the aircraft will be at a time in the future.
17.0 Summary of Automation Interactions
The TBO automation is a complex set of tools that support flight planning and execution. Throughout
this report, many current and planned automation elements have been mentioned. However, there is
clearly a lack of integration of functions or information. Therefore, this summary provides automation
functions that follow a flight from a higher level of function. This summary would be a starting point
for developing a functional decomposition and the necessary linkages to domains of flight operations.
TBO is integral to flight planning and execution. NextGen is expected to link the ANSP and the
operators together with unprecedented connectivity through network-enabled operations, delivering
and exchanging information in near- to real-time. For TBO, this exchange includes the flight plan and
the flight object that carries the necessary 4DT information required by automation. It is likely that
only changes would be sent to and from the aircraft as part of data link communications. The elements
of this information exchange are designed to provide common situational awareness, knowledge of
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