Trajectory-Based Operations (TBO) - Joint Planning and ...
Trajectory-Based Operations (TBO) - Joint Planning and ...
Trajectory-Based Operations (TBO) - Joint Planning and ...
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<strong>Trajectory</strong>-<strong>Based</strong> <strong>Operations</strong> (<strong>TBO</strong>)<br />
Study Team Report<br />
Conformance monitoring for the 4DT supports a much smaller horn of uncertainty, 24 in that most of the<br />
variability is now longitudinal in terms of time. Winds aloft will require frequent updates of the 4DT.<br />
En route <strong>TBO</strong> automation will use conformance monitoring, flight object, aircraft position, intent, <strong>and</strong><br />
similar information from all other aircraft to look for downstream conflicts. It will do so by using the<br />
ANSP strategic <strong>TBO</strong> evaluation services.<br />
When a downstream flow contingency like weather must be considered, trajectories are reworked for<br />
aircraft using the airspace, all the way back to the departures <strong>and</strong> forward to the l<strong>and</strong>ings. This<br />
reworking is a continuous process that produces options that can be strategic (greater than 20 to 30<br />
minutes in the future) or tactical (within 20 to 30 minutes). Strategic options can be shared with airline<br />
operations/dispatch, since there is time to provide options for negotiation. Within the 20 minute<br />
horizon, the controller shares options with the flight crew who can select their preferences. Once an<br />
option is selected, the en route <strong>TBO</strong> automation uses this information to update the 4DT <strong>and</strong>, with new<br />
intent information, receives intent verification from the aircraft through data link that the changes on<br />
the flight deck have been implemented. The ANSP <strong>TBO</strong> evaluation service receives information on the<br />
selected choice <strong>and</strong> updates the aircraft’s flight object for use in continuous 4DT <strong>and</strong> flow evaluations.<br />
In some cases, the changes must be more tactical—a heading, speed, or altitude change. The aircraft,<br />
when given this new clearance, is on an open trajectory. The open trajectory continues until a new<br />
point in space <strong>and</strong> time is defined <strong>and</strong> the 4DT is updated.<br />
The advantage goes to the equipped aircraft. The more capable the aircraft is, the more likely the<br />
desired choices are known to the ANSP, <strong>and</strong> the easier it is for the ANSP to manage the aircraft. An<br />
aircraft that is less equipped <strong>and</strong> in the airspace will require more work to implement a change in<br />
trajectory.<br />
Conformance monitoring parameters include the altitude, lateral displacement, longitudinal flight<br />
track, <strong>and</strong> separation based on time, <strong>and</strong> time to the next point reported in intent. All monitoring<br />
parameters can be adjusted based on traffic density <strong>and</strong> the need to meet downstream commitments for<br />
separation, sequencing, <strong>and</strong> merging. The parameters are derived from a combination of the<br />
performance requirements from the ANSP strategic <strong>TBO</strong> evaluation services <strong>and</strong> operator/pilot<br />
capabilities <strong>and</strong> preferences. A business aircraft at FL 450 will have a different set of conformance<br />
constraints than an air carrier aircraft at FL280 waiting to merge into an overhead stream at FL320. An<br />
aircraft heading to a tightly controlled merge point or metering point may have a very tight time<br />
performance, whereas another aircraft may have flexibility in time of many minutes. The parameter<br />
tolerances for each aircraft are bounded by the performance capabilities of the aircraft, its crew <strong>and</strong> the<br />
needs of the ANSP.<br />
En route <strong>TBO</strong> automation supports:<br />
• Considerable merging <strong>and</strong> sequencing<br />
• Information on gaps in overhead streams to the ANSP strategic <strong>TBO</strong> evaluation service <strong>and</strong> to<br />
counterpart departure <strong>and</strong> arrival <strong>TBO</strong> automation<br />
• Blocks of vertical airspace for military special use <strong>and</strong> aircraft cruise climb maneuvers<br />
24<br />
The horn of uncertainty is a 3D representation of windows of reserved airspace in vertical, lateral,<br />
<strong>and</strong> longitudinal axes requiring reservation for the aircraft based on its performance.<br />
<strong>Joint</strong> <strong>Planning</strong> <strong>and</strong> Development Office<br />
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