How Continental Landed On Its Feet

By Peter Horner

Anna White, director of Crew Technology at Continental Airlines, had never faced a situation like this before. Neither had anyone else in the history of commercial aviation. When President Bush ordered a shutdown of the national air transport system following the Sept. 11 terrorist attacks, those professionals in the airline industry charged with devising viable, cost-effective flight and crew schedules were staring at a worst-case scenario beyond any of their imaginations.

"Within an hour, our entire fleet was grounded at the nearest available airports," White recalls. "We literally had hundreds of planes that were not in cities they were originally scheduled for. We had thousands of crewmembers who were not in the cities they were originally scheduled for. It was a monumental problem. I can honestly tell you that in the 19 years I've worked in crew operations, I had never seen anything like it."

All airlines experience disruptions — major and minor — to their network on a fairly regular basis. Last year alone, snowstorms twice closed down Continental's hub airport at Newark, N.J, and flooding shut down Continental's hometown Houston hub on another occasion And that's not counting the dozens of minor disruptions that occur almost daily.

"Typically, when bad weather happens, it's usually isolated to a hub or region," White says. "Some of your operations continue from a quasi-normal standpoint. Obviously, if bad weather hits the East Coast, it impacts some of your operations on the West Coast because flights connect and passengers go through. In this case, we had a total disruption to 100 percent of our operation with no pre-planning."

Under "normal" disruption circumstances, an airline will try to get back on schedule as quickly and as cost-effectively as possible. Following Sept. 11, "It wasn't so much a case of putting Humpty-Dumpty back together again, it was trying to get things in position so we could manage our resources again," White says.

Before Sept. 11, Continental employed more than 3,000 crewmembers and deployed 350 aircraft to cover 1,400 flights a day. All operations ceased until Sept. 14.

"We had to go in and figure out what we were going to do with those crewmembers and what we were going to do with those flights and pairings," White says. "We knew the schedule would be gutted — by 40 percent the first few days back, and by 20 percent for the rest of September. The problem was, how could we match the resources we had to cover the flights as effectively as possible within the guidelines of our contracts and [federal regulations]? We had more than 3,000 crewmembers and more than 1,300 pairings that were disrupted. We weren't returning to normal operations. We were trying to normalize irregular operations."

A crew "pairing" is an optimized matching of pilots and flight attendants for a series of flights that start and end at a hub. The pairing can comprise one to four days' worth of flights. Continental classifies its crew pairings by the type of aircraft in its fleet — 747s, MD80s and DC10s. After Sept. 11, White says those pairings turned into "fractured fairy tales."

"The problem was so large, I don't know where we would have started without CrewSolver," continues White, referring to the disruption management and recovery software developed by CALEB Technologies Corp. "It was sort of like trying to find a needle in a haystack and go from there. What the software allowed us to do was basically throw every pairing that had been disrupted — which in this case was every pairing that operated — and optimize those pairings using the rules we have for crew recovery to cover the flight schedule and bring our crew members back home."

White estimates that without the OR-empowered software, it would have taken "several people working on the problem for three or four days before we could start flying again from a crewmember standpoint." Using the software, the airline optimized each aircraft solution (737, MD80 and DC10) in a matter of minutes. Because the revised schedule was continuously updated as more information became known prior to the resumption of operations, the airline ran several optimization iterations over a 20-hour period. On Sept. 14, the CrewSolver system resolved about 1,600 problem pairings with Continental's 737 and MD 80 fleets in 17 minutes.

Meanwhile, Continental used another CALEB product, OpsSolver, to sort through millions of variables and thousands of constraints to create complete solutions for the airline's 350 aircraft and 1,400 daily flights. In addition to optimally canceling and rescheduling flights, OpsSolver also removed all of Continental flights in and out of Washington's Reagan National Airport, which had been closed indefinitely.

Having introduced OpsSolver and CrewSolver in the third quarter of 2000, Continental was well aware of the software's capabilities prior to Sept. 11. In January of last year, for example, one of the worst winter storms in recent history dumped 25 inches of snow on New York and New Jersey, snarling the region's three big airports and closing Continental's hub in Newark. Using CALEB software, Continental crew coordinators rerouted more than 350 flight crews in minutes.

Given days to recover after the terrorist attacks, most airlines resumed operations on Sept. 14 when the airspace was reopened. White believes Continental recovered "in a more organized fashion" than most thanks to the airline's high-tech solutions and communications. "When we started back up, our crewmembers had all the information they needed," White says.

As for the passengers, White says the reports she heard from the front line indicated that "the attitude of the people who flew with us that first day back was overwhelmingly positive. They were glad to be going home, and they were glad they were flying home with us."

Peter Horner is the editor of OR/MS Today.