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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 in order to maximize efficiency.  There are a number of 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 continues to participate in a number of Trajectory Based Operation (TBO) groups/initiatives including the TBO Training group, TBO Procedures, and the TMC Training Group.  These meetings target certain objectives within TBO and representatives from various offices collaborate together with not just TBFM Ops NATCA SME’s but SMEs from other groups as well. These Collaborative Work Groups (CWG’s) also extend out to Geographic Operating Areas that the Ops SME’s work with as well. These currently include the Northeast Corridor, Northwest Mountain, and Southwest Operating Areas. As these groups are beginning to work together on TBO related goals and initiatives the TBFM Ops Team will continue to support when and where necessary to ensure that these groups have the best support they can to make decisions on the initiatives moving forward. 

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 ZNY and ZBW to schedule departures directly into the ATL and 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.   

Technical requirements to a major enhancement to the TBFM system is being worked on by TBFM Ops Team representatives, FAA Second Level Engineering (SLE), Contract support and the TBFM contractor Leidos. This enhancement will be to allow much greater flexibility and dynamic usage of the Future Change Capability within TBFM. This Future Change capability is used to change certain parameters within TBFM at specified times.  Currently this capability is very limited in not only how it’s used, but in the frequency of use as well. These changes will allow Traffic Management Coordinators (TMC’s) a much greater flexibility to better utilize the system and work through operational changes while continuing to utilize TBFM. 

Terminal Sequence and Spacing (TSAS) 

Paul Carroll is the TSAS NATCA Subgroup Co-Lead 

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 will more than likely be delayed. 

Software Updates- the Team participated in numerous software telcons and provided input on several software decisions for both TBFM and TSAS. The latter part of December was quiet due to many employees on leave.   


We were briefed by the Tech Center about the various techniques they are employing to assist with social distancing in the lab, such as staggering control positions and having them face in opposite directions.  We are hoping to test in the lab soon.  Until then, we will continue to work with the Program Office to explore additional ways to improve the display quality while we attempt to remote test software to the best of our abilities.  

Training and Implementation- the Team held a Training Curriculum meeting on December and have three additional meetings planned for late January and early February. The Program Manager advised us that due to budget constraints, he is cancelling all but one of the scheduled meetings. We will meet with the training contractors to prioritize what work needs to be done with the curtailed training meetings. The Team added several new risks, associated with COVID 19, to the Risk Management list. The Agency will track these issues and if necessary, implement mitigations for them. The TBFM Ops Team welcomes new member Paul Phillips from Atlanta TRACON. Welcome aboard Paul!   

Upcoming Activities: 

  • Evaluations, Inspections, and Peer Reviews of future TBFM build content. 
  • Continued 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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