Most frequent fliers are familiar with long lines at airports: at the check-in counter, the departure gate, and in boarding a booked flight. But even after passengers are buckled in, the waiting may continue — when a plane leaves the gate, only to sit on the tarmac, joining a long queue of flights awaiting takeoff. Such runway congestion can keep a plane idling for an hour or more, burning unnecessary fuel. Now engineers at MIT have developed a queuing model that predicts how long a plane will wait before takeoff, given weather conditions, runway traffic, and incoming and outgoing flight schedules. The model may help air traffic controllers direct departures more efficiently, minimizing runway congestion.
Hamsa Balakrishnan, an associate professor of aeronautics and astronautics and engineering systems and an affiliate of the Institute for Data, Systems, and Society at MIT, says that in tests at various U.S. airports, the model encouraged controllers to hold flights back during certain times of day, leading to significant fuel savings. “In our field tests, we showed that there were some periods of time when you could decrease your taxi time by 20 percent by holding aircraft back,” Balakrishnan says. “Each gate-held aircraft saves 16 to 20 gallons of fuel, because it’s not idling. And that adds up.” Balakrishnan and former graduate student Ioannis Simaiakis have published their results in the journal Transportation Science. The team is working on airports across the country to further test the model. Read more