• Using a NextGen tool, on-time arrivals at Fort Lauderdale-Hollywood International Airport were up 2.5 percent during the 2013 snowbird season despite only having one working runway.
  • Arrival delays declined 10.7 percent, which averages five fewer delayed flights per day.
  • Average delays decreased by 1.1 minutes (2.1 percent) for those flights that were delayed.
    (Source: ASQP)
NextGen procedures helped planes land on time even when one runway was closed at Fort Lauderdale-Hollywood International Airport.

NextGen Implementation Plan (PDF)

Time Based Flow Management (TBFM)
Enhances system efficiency and improves traffic flow by leveraging the capabilities of the Traffic Management Advisor decision-support tool, a system that is already deployed to all contiguous U.S. Air Route Traffic Control Centers.

Every winter, flocks of "snowbirds" make their way from chilly northern climates to Fort Lauderdale-Hollywood International Airport and the sunny beaches of south Florida. To better accommodate the 1.2 million passengers who use the airport every month during winter and spring, which makes it one of the United States' busiest, the airport is building a new 8,000 foot long elevated runway, replacing a shorter runway, to improve efficiency and reduce delays. Only one runway is operating at the airport during the 16-month final phase of construction, so timing is everything. A NextGen tool that helps air traffic controllers time arrivals to keep a steady flow of aircraft going onto the single runway is helping keep delays to a minimum.

Airport, airline and FAA officials spent three years planning for single runway operations. Their goal was to make sure delays didn't mount to the point that they would put a damper on the local economy. Since construction started, air traffic controllers have been using a NextGen decision support tool called Time Based Flow Management (TBFM) and other traffic-management techniques to keep traffic moving safely and efficiently and minimize delays.

The planning and close collaboration paid off.

"We tried to forecast what the average delay would be like during single runway operations. What we have achieved in terms of minimizing delay is significantly better than forecast," said Doug Webster, deputy director of aviation for the Broward County Aviation Department.

It's working so well that on-time arrivals were actually up, not just maintained at the same level, and arrival delays were down. During the 2012-13 snowbird season (November — April), 2.5 percent more flights arrived on time compared to the same time-period during the 2007-08 snowbird season before construction started. Arrival delays declined by 10.7 percent with 1,037 fewer delayed arrivals, which is five fewer delayed flights on a daily basis. For those flights that were delayed, the average delay was reduced by 1.1 minutes (2.1 percent). On-time gate arrivals and departures also improved by 2.6 percent and 1.0 percent respectively. At the same time, average gate arrival delays decreased by 10.6 percent and gate departure delays decreased by 8.7 percent.

The controllers' goal is to feed aircraft into the flow for landing at a steady pace and with just the right interval between each touchdown. Timing is critical. Controllers have to allow enough time following a landing for a departing aircraft to taxi onto the runway and take off without blocking the next arrival. And to make sure landings and departures happen without delays, there has to be just the right amount of spacing between aircraft so the runway can be used to its maximum capacity when necessary.

Having an interval too short between landing aircraft means there is not enough time to clear an aircraft for departure in between, thus wasting a departure slot. Having an interval too long means that time is being wasted on that particular arrival, and wasted time adds up to fewer takeoffs and landings over the period of a day. During high-volume traffic periods, this means that arriving aircraft may need to slow down to maintain the correct intervals. It's more efficient to have aircraft slow down while still cruising in high-altitude airspace, because aircraft burn less fuel the higher up they are.

TBFM helps controllers manage arrivals by calculating when each aircraft should reach a specific point in space about 200 miles away from the airport to reach the runway at the desired time. One aircraft may need to add a minute of flying time, another two, and yet another may be able to proceed without delay. Before TBFM was available, controllers spaced arriving aircraft with a set number of miles between each, which did not make the best use of available landing slots.

TBFM also helps controllers orchestrate departures at Fort Lauderdale so the aircraft taking off can merge with the flow of traffic at cruising altitudes.

By using TBFM during busy periods, controllers are able to keep delays under control and sustain 24 arrivals and 24 departures an hour on the runway when traffic lands from and takes off toward the west. When the winds shift and the traffic lands and takes off to the east, TBFM helps sustain a rate of 28 arrivals and 28 departures an hour. Before the construction, when both runways were in use, the airport handled 38 arrivals and 40 departures with operations to the west and 42 arrivals and 40 departures with operations to the east.