David Lovell

Funding Agency





This is an 18-month, $100,000 subcontract to Leidos for Collaborative Decision Making with Time Based Flow Management. Lovell will develop software for simulation and comparison.

The Time Based Flow Management (TBFM) system enables controllers in the Traffic Management Unit (TMU) or Air Route Traffic control Centers (ARTCCs) to manage air traffic on a strategic basis by inputting miles-in-trail (MiT) and other restrictions to derive a time-based schedule for flights arriving into or departing from certain airports.

TBFM provides the ERAM controller with metering times at certain constraint satisfaction points (CSPs) in order to regulate air traffic over extended metering points (XMPs) and coupled metering point (CMPs) typically located anywhere between 100 NM and 500 NM from an arrival airport, and meter fixes (MFXs) situated 60 NM to 100 NM from the arrival airport. It also allows the user to schedule departing flights into an overhead stream of traffic.

To manage the balance between demand and capacity at an airport, TBFM allows the user to specify airport arrival rates and inter-aircraft spacing between flights at a runway based on airline, weight class and other characteristics. Most of the constraints input into the TBFM system result from discussions between ARTCCs as well as the Command Center in Herndon, VA.

Unless an airport is serviced by one or two dominant airlines, rarely do they have a say in the setup and use of TBFM. While airlines can receive and analyze TBFM data through the Metering Information Service (MIS), they cannot specify particular settings in order to influence the sequence and schedule of flights; collaborative decision making concepts, have not been integrated into TBFM to this date. Collaborative decision making in relation to Air Traffic Management (ATM) seeks to ensure that information relevant to the efficient running of the National Airspace System (NAS) is shared amongst various stakeholders and decisions are made using the best information possible. As defined by ICAO “A process focused on how to decide on a course of action articulated between two or more community members. Through this process, ATM community members share information related to that decision and agree on and apply the decision-making approach and principles.”

Within the US, CDM involves both industry and government and seeks to create a common platform with common information that can be used by all stakeholders when making decisions, with the goal of creating a safe, efficient and secure NAS. A simple form of CDM is already in place today—ARTCCs hold multiple teleconferences daily with the Command Center to determine any traffic management initiatives (TMIs) that are needed to make best use of the available resources. These TMIs are typically translated into MiT that can be input into the TBFM system. However, many other CDM concepts exist such as allowing an airline to dictate the flights that receive particular arrival sequence slots or for airlines to swap slots between themselves in order to meet their schedule and revenue objectives. However, airspace management programs such as TBFM do not have a way to ingest data available from the airlines and process it to influence the generated schedule.

TBFM could benefit from a variety of CDM concepts and produce a schedule that is amenable to both the air traffic controllers and airlines. For example, if TBFM knows in advance that a departure is going to be delayed on the ground and a position in the overhead stream has been reserved for this flight, information from the airline could result in TBFM swapping the slot in the overhead stream for this flight, with another belonging to the same airline. Airlines could look at the STAs being assigned to their flights and provide TBFM with relevant information such that the sequence of flights could be tailored based on operational need. Many more CDM concepts exist that could benefit the generation of a schedule by incorporating airline needs, ATC needs and potentially requests from other stakeholders.

The objective of this work is to determine the CDM concepts that will have the largest impact on TBFM and formulate a method to incorporate them into TBFM’s schedule building algorithm. The creation of a schedule in TBFM involves the solving of an optimization problem with the objective being to keep delays down to a minimum while adhering to constraints such as MiT and sequence enforcement (some cases). Introducing CDM concepts will involve including additional constraints into the optimization problem that could make it difficult to arrive at a schedule. Another goal of this work would be to determine the CDM concept that has the biggest benefit to users of the TBFM system while keeping the optimization problem, minimally constrained and avoiding the loss of slots at an airport, i.e, keeping the maximum amount of pressure on the runways.