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

Trajectory-Based Operations (TBO)
Study Team Report
Some small pop-up convective weather cells are beginning to appear along the arrival route. The
ANSP, using the TBO arrival decision support tools with integrated weather information, plans a
temporary modification to the initial segment of the arrival route to avoid the weather cells by adding
two new waypoints. Both Transcon 1324 and Sunset 123 receive arrival route modifications, which
they load into their FMSs. Since they are still more than 60 nm from the airport, they have sufficient
time to rejoin the original route and make up lost time for efficient final spacing. Both aircraft have
the same highly accurate terminal area wind profile data as the ground automation, facilitating accurate
trajectory prediction and efficient OPDs. By using ADS-B and data link access to network-centric
operations, the aircraft receive information on terminal area conditions and all approaching traffic.
The flight object also includes a pre-clearance taxi plan for post-landing surface operations generated
by surface movement TBO automation systems, and based on predicted touchdown time generated by
IAD TBO arrival management automation. This may be updated as situations change.
Approach:
As Transcon 1324 and Sunset 123 conduct their respective approaches, the ANSP monitors
conformance for each aircraft. The assigned routes are configured such that 23 nm from the runway,
Transcon 1324 levels off at 2,500 feet altitude and Sunset levels off at 1,500 feet altitude, so they are
on parallel courses 750 feet apart laterally, but separated vertically by 1,000 feet. Since Transcon 1324
has been assigned to be the initial follower in the VCSPR pairing, it is responsible for positioning the
aircraft with the appropriate longitudinal spacing with respect to Sunset 123 before reaching the
coupling point 12 nm from the runway. This is accomplished using speed guidance provided by
onboard spacing tools. Both aircraft are cleared for the VCSPR operation before either aircraft
intercepts the three-degree glide slope.
If Transcon 1324 had not achieved the required spacing by the coupling point, it would have been
required to conduct a missed approach at that point. During the VCSPR operation, both Transcon 1324
and Sunset 123 are flying coupled-autopilot approaches with highly precise lateral navigation. Both
aircraft are using onboard alerting algorithms to monitor the other aircraft for indication of a possible
blunder, which would necessitate a breakout maneuver. The alerting algorithms are using applicationspecific
information transmitted via the ADS-B intent message, such as position, bank angle, and
autopilot and navigation status information.
As each aircraft intercepts the glide slope, Transcon 1324 continues to actively space off of Sunset
123, staying towards the back of the conformance zone. After the FAF, the two aircraft slow to their
respective FASs and are in their landing configurations by the SAP three nm from threshold. At the
three nm point, active spacing ends and each flight crew maintains their respective FAS and focuses on
safe landing. Since Transcon 1324 has FAS that is 10 knots faster, Transcon 1324 passes and touches
down ahead of Sunset 123.
Before touchdown, the ANSP clears both aircraft for Segment 1 (through runway exit) of the taxi plan
(the ANSP can cancel green status and issue a missed approach if necessary.) The flight crews
acknowledge the clearance via voice and visually inspect the runway as the aircraft approaches for
touchdown. Under instrument conditions or at night, a glance at the CDTI will show aircraft that may
be on the runway. Onboard alerting exists for runway incursion prevention.
Joint Planning and Development Office
58