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

Trajectory-Based Operations (TBO)
Study Team Report
trajectory updates to the controller, possibly before the aircraft start requesting them, both to optimize
overall system flows and to reduce communications. For instance, if winds are more strongly out of the
west than forecast at Dallas-Ft. Worth (DFW), all the flights from the west coast will be arriving early,
and those from the east coast will be arriving late. This will trigger revised times at the arrival fixes.
Users may include predefined preferences (similar to the FMS cost index function) with the filed flight
plan for ANSP automation to consider in proposing alternative trajectories.
The ANSP may negotiate by proposing revised constraints to the aircraft or the FOC, and let the
operator choose a preferred trajectory to meet the constraints. This new preferred trajectory could then
become the authorized trajectory that now has to be renegotiated if a further change is required. This is
likely to be the case when the ANSP is using the trajectory for separation management.
Performance requirements for airspace and operations will generally be set before flight, but
occasionally might be used opportunistically during flight. This might occur, for instance, during
en route convective weather, where the ANSP negotiates optimal routes for high-performing aircraft
(data link, low RNP) through gaps in the weather, and lower performing aircraft are routed around it.
In this example, the better-equipped aircraft gets the advantage of using the more direct route.
5.8 Flight Planner-Initiated Trajectory Negotiation 4
The dispatcher is typically a person responsible for managing flights; one or more dispatchers perform
their work in a FOC. For single-aircraft operations, the flight planning function may be performed by
the pilot in command, member of the flight crew, or another entity on their behalf such as a flight
service station, or to a third-party company who offers collaborative air traffic management (CATM)
service to Part 91 operators.
The flight planner’s horizon for negotiating a flight may vary from tens of minutes to weeks. Typical
reasons for negotiating a trajectory with the ANSP include the following:
• For an airline, build and update a schedule for its overall flight operation to meet the schedule
• Get best initial trajectory for individual aircraft before takeoff
• Prioritize among multiple flights (under the flight planner’s jurisdiction) entering congested
airspace or terminal area
• Re-route, delay or substitute one or multiple flights around weather or congestion to maintain
business objectives
• Diversion from original planned destination due to severe conditions, weather, fuel needs,
aircraft emergency, passenger considerations, etc.
The FOC will maintain a model of the aircraft performance and other key characteristics to anticipate
the expected flight progress in the given environment, fuel usage, etc. This information informs the
flight planner of what trajectory options are feasible for the aircraft when negotiating a new trajectory
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In negotiating flights with the ANSP, one of the factors affecting the options available to the operator
is equity. It is assumed that there is policy in place for addressing equity among flight operators. The
rules that define equity are beyond the scope of this report. Likewise, CATM is explored further in the
RTCA Trajectory Operations Concept of Use efforts and is not duplicated here.
Joint Planning and Development Office
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