Tools Used for Traffic Flow Management

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Unified Delay Program (UDP)

The UDP is a new type of traffic management initiative that is designed to be more efficient and equitable in how delays are assigned when an airspace constraint exists. It can be described as a new "mode", in which both ground delay programs (GDPs) and Airspace Flow Programs (AFPs) can be run.

However, the Unified Delay Program (UDP) has some new elements that could have a significant impact on operators.

Until the advent of the UDP, ground delay programs (GDPs) and airspace flow programs (AFPs) could be run in one of two modes – the Delay Assignment (DAS) mode or the GAAP mode. Learn more about DAS mode GDPs and GAAP mode GDPs.

With both types, traffic flow managers would determine how much traffic a particular airport or section of airspace could handle per hour and then apply delays evenly to flights headed into the constrained area to keep the traffic rate below what could be handled per hour. In the case of a GAAP, traffic managers would build empty slots into each hour of the program in order to accommodate "pop-up" or "late-filer" flights.

What is Different About UDPs?

A delay program run in UDP mode is designed to combine the DAS and GAAP concepts into a single tool, easing the workload of traffic managers and making delays more equitable.

However, operators who file into an existing UDP late could face substantial delays. This is because a UDP will first assign whatever the average delay is for the program before trying to find the next available slot. If a slot is not available for several hours, the delays could quickly approach the maximum (up to 360 minutes).

In fact, ANYONE who files a flight plan into a UDP after the program has been issued will receive an expect departure clearance time (EDCT) with an extended delay. In other words, a flight that would have been considered exempt from delay in the UDP, had the operator filed before the program was instituted, would experience a significant delay if the plan is filed after the program starts.

What Do Operators Need to Know About UDPs?

First, operators should learn to be aware of what is happening in the National Airspace System (NAS) long before their flight is scheduled to depart.

NBAA recommends that, as part of their flight planning process, operators should utilize the FAA's online tools, such as the Operational Information System (OIS) and Advisories Database at least 8 hours before their planned flight to see where UDPs are expected or even possible.

Perhaps more importantly, since the FAA plans to run the vast majority of GDPs and AFPs in UDP mode, it is increasingly important for operators to file their flight plans well in advance of an implemented UDP in order to ensure that they are considered to be "known demand" – meaning that their flight plans are in FAA's Traffic Flow Management System (TFMS) BEFORE a UDP is implemented. If possible, filing flight plans the night before a flight is a great practice.

Finally, a word of caution for operators utilizing a flight plan service provider to file their flight plans. Some providers will accept flight plans from operators or wait to file them until as little as 2-3 hours in advance of a flight. As a result, it is recommended that operators advise their service providers to ensure that their flight plans get into FAA's TFMS at least 8 hours in advance of the flight.