Getting Around: Storms sock on-time numbers at O'Hare

"The airlines won't normally cancel flights based on projected thunderstorms," Flynn said. "They are going to keep the system running, pressure the air traffic control system as hard as they can until the thunderstorm actually appears."

The strategy often results in delay buildups that are difficult to recover from over the course of the day, FAA officials said. And with planes flying with almost all the seats full, the airlines are hesitant to cancel flights, Flynn said.

For several days this month, O'Hare controllers were busy handling passenger flights until about 1 a.m., or several hours past the normal time, because of backlogs, he said.

Passenger Arlene Brewer got caught in the conflict between weather and airline scheduling while trying to get home to Philadelphia from Los Angeles via O'Hare last week. The flight to Chicago was uneventful, Brewer said, but as a series of thunderstorms intensified, her final leg was canceled.

"I am being rebooked on a later flight, but I don't have a good feeling," said Brewer, 59. "I try to improve the odds by traveling early in the morning, but with airfares being so high you can't always afford to fly direct so you end up partway home."

The economics of the industry dictate that "the airlines are going to schedule to what the airport can handle on a good-weather day," said Jim DeYoung, managing director of network operations at United. "We are in the business to make money so we are going to schedule to an airport's capacity to the extent we can."

United is making a big push to get passengers seated and flights out of the gate before the scheduled departure time when possible, to take advantage of breaks in weather and airport congestion, DeYoung said.

Aircraft doors are still closing 10 minutes before the scheduled pullback time, which is why most airlines recommend that travelers show up at the gate at least 30 minutes prior to flight time.

When lightning strikes are reported within 5 miles of O'Hare, airfield workers must come indoors for safety. But United and American are able to keep taxiing aircraft up to the gates to park and let passengers out.

United relies on a low-tech Park at Any Time System, or PATS. It involves a truck equipped with lights on top of the cab guiding the pilot to steer the jetliner along the parking ramp pavement's painted center line to a "stop" bar at the gate, DeYoung said. The jet bridge is then extended to the plane door.

American, meanwhile, uses an automated airplane guidance and docking system at each gate.

The centerpiece of the docking system, which American likes so much it uses it year-round, is a laser beam that identifies the airplane bound for the gate based on its aircraft type, said Rob Cumley, airport services manager for American at O'Hare.

A Tribune reporter stood outside on the ramp at Gate K-2 during a rain shower last week as an MD-80 airplane docked. A digital screen posted above the gate displayed the flight number and provided a countdown to the pilot regarding how many more feet to continue taxiing before stopping. Left or right arrows also flashed on the screen if the pilot deviated even slightly from the parking center line.

"The system reads American's flight schedule, and it scans the field for the arriving aircraft it is looking for," Cumley said. "To me, the docking system paid for itself the first time a thunderstorm hit and everybody was inside but the airplanes were still parking. We and our passengers aren't out on a taxiway holding for an hour with the engines running until the weather clears."

In addition, American over the last three weeks at O'Hare has introduced a new on-screen system that its traffic planners use to increase their awareness of the exact location on the airfield of the planes they are directing, said Tony Markowski, American's director of tower and ramp operations at O'Hare.

Called Vantage Point, it replaced a paper-and-pencil system that had been used for decades.

"It takes out some of the guesswork," Markowski said, adding that he expects the technology will create efficiencies that lead to more on-time connections for customers.

As he spoke, inside American's minitower at O'Hare that overlooks the alleys where the parking ramps are located, tower planner Matt Lobben used the Vantage Point software to squeeze out a departure from Gate K-10 two minutes before its scheduled push-back while an incoming flight that had just landed was taxiing to K-10.

Without the bird's-eye view that Vantage Point provided — showing the incoming plane still had some distance to taxi — Lobben would have had to play it more conservatively.

The FAA's revised summer strategy also involves finessing complicated air traffic procedures that dictate when and for how long planes are held on the ground at congested airports because of active or approaching storms, officials said.

Once planes are airborne, there is another priority: preventing excessive holding patterns, where jets circle in vertical tiers that approximate a multilayered cake, officials said.

A related goal is reducing the likelihood that passengers will be diverted to a secondary airport as the result of weather, officials said. And when diversions must occur, the airlines will attempt to avoid hamstringing the diversion airports with more aircraft and more tired, hungry passengers than the facilities can handle.

"We have a very robust plan now to hopefully avoid oversaturating our diversion airports when a storm is overhead Chicago," DeYoung said.

If the carriers can't get travelers to their destinations on time because of weather, the goal is to notify passengers early on when flight delays are brewing.

"We don't yet have the level of certainty based on the weather to tell a specific customer who is sitting at home that it's 12 p.m. now and your 4 p.m. departure is going to be delayed two hours. But we can at least use the reservations system to alert customers that delays are likely in Chicago or in Newark (N.J.) and to give them some level of predictability," DeYoung said.

Contact Getting Around at jhilkevitch@tribune.com or c/o the Chicago Tribune, 435 N. Michigan Ave., Chicago, IL 60611; on Twitter @jhilkevitch; and at facebook.com/jhilkevitch. Read recent columns at chicagotribune.com/gettingaround.

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