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Time Based Flow Management (TBFM)

Matt Gammon is the Article 114 Representative for Time Based Flow Management (TBFM) 

Background:  Time Based Flow Management is a system of tools used to manage flows of traffic based on time to maximize efficiency.  There are several technologies within TBFM to include but not limited to Airborne Time-Based Metering, Integrated Departure Arrival Capability (IDAC), EnRoute Departure Capability (EDC) and Terminal Spacing and Sequencing (TSAS).  Airborne Metering applies spacing where needed by having aircraft meet scheduled times at constraint points to balance demand with capacity and optimize flows of traffic into a terminal area. EDC is a scheduling capability within TBFM to Manage Miles-in-Trail restrictions when needed. IDAC specifically allows not only for automated release requests/acceptances, but also allows Towers to get insight into future constraints for planning purposes. 

The TBFM Ops Team received a Remote Demo of the 4.13 TBFM system. This was just an initial look at what content will be in the 4.13 build.  The 4.13 build will be entirely to accommodate TFDM system needs.  TBFM Ops Team members have begun working with Leidos and the TFDM group to identify needs and work through issues that may arise.  This build will be factory only meaning it will not be release to the field, but the content will be in future releases as necessary to support TFDM. Additionally, a Safety Panel was held for the TBFM 4.14 Future Release and the Ops Team participated in that activity. The 4.14 will be the next major TBFM release after the upcoming 4.10 National release tentatively scheduled for the spring of 2021. 

Continued work and finalization of plans for support has been conducted for an enhancement to the TBFM system at Atlanta Center (ZTL) and Jacksonville Center (ZJX).  This enhancement will allow for select Towers in ZJX to schedule departures directly into the ZTL TBFM EnRoute Departure Capability (EDC) system to meet Miles-In-Trail (MIT) restrictions.  In addition to the enhancement work for ZJX the Ops team is working on a future enhancement to allow New York Center (ZNY) and Boston center (ZBW) to schedule departures directly into the Atlanta (ATL) and Charlotte (CLT) Arrival TBFM system.  These initiatives will not only reduce the amount of MIT restrictions but also allow for greater visibility to both the scheduling and receiving facilities.  These enhancements will also work with Tower IDAC scheduling systems as well to ensure that any current departure scheduling capability is not lost. 

The TBFM Ops Team continues to support Trajectory Based Operations (TBO) and specifically the TBO training group to work towards future TBFM training for EnRoute controllers and TMC’s.  Specifically, there was a final review of updates to IDAC ELMS Training material.  The team also received a demo/info regarding how TBFM processes the scheduling of departures into the system.  This was led by Second Level Engineering (SLE) and their support contractor and has allowed the Team to get a more in-depth understanding of how TBFM builds a schedule. This understanding is important as Ops Team SMEs are often called upon to help field Air Traffic personnel write local TBFM adaptation requirements. 

Terminal Sequence and Spacing (TSAS)  

Paul Carroll (PCT) TSAS NATCA Subgroup Co-Lead 

Background:  Terminal Sequencing and Spacing (TSAS) is a new technology that is under development.  TSAS is an extension of Time-Based Flow Metering (TBFM) into terminal airspace. The system provides controllers with several tools including speed advisories to maintain a predetermined sequence to a runway/s without extending the downwind.  TSAS is a key component of Trajectory Based Operations (TBO).  Denver TRACON is the first key site with a scheduled date of December of 2022.  Due to delays caused by the Covid 19 outbreak, the implementation date may be delayed. 

Software Updates 

The Team continues working on software fixes with Leidos and Raytheon along with Second Level Engineering (SLE) and Terminal Second Level Engineering (TSLE).  Leidos continuously releases software fixes in interim builds in TBFM.  The Team is working with TSLE to provide controls on the STARS DCB/keyboard entries to control the display of TSAS Tools on Quick Looked sectors. We have submitted several requests for software enhancements over the past month.  


Remote testing of TSAS is arduous.  The clarity of the display and remote interaction with the TBFM/STARS systems prove to be extremely difficult.  We are working with the Program Office to explore ways to improve the display quality.  In addition, interaction with both TBFM and the STARS TCW in the remote environment is time consuming.  We try to close Problem Reports (PR’s) and Discrepancy Reports (DR’s) for any items we are able to evaluate in the remote environment.  We have scheduled in-person testing at the Tech Center for next February, however, due to Covid limitations there will be severe limits on the personnel that can attend. This is subject to change at any time based on Covid impacts.   

Training and Implementation  

The Team held a Training Curriculum meeting on Dec. 14 and have three scheduled after the New Year.  We are in the process of reviewing the TSAS content on the STARS R10 training materials.  We have yet to finish the STARS material but should finish at the next meeting.  We continue tracking the risks induced by Covid and evaluate the impact to the program as we move toward IOC.  We attended a meeting with personnel from SCT to continue the local software adaptation for TSAS.  We will continue to have meetings with them after the New Year until the initial adaptations are complete.  

Upcoming Activities: 

  • Evaluations, Inspections, and Peer Reviews of future TBFM build content. 
  • Work with Trajectory Based Operations Group (TBO) Training workgroup with a focus on future standard Controller training for TBFM Airborne Metering. 
  • Continuing usage of TBFM developmental server for Ops Team SMEs. 
  • Review of tickets, planned training, and other activities for Sustainment, Northeast Corridor (NEC) TBFM & Western Area TSAS implementation. 
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