Jun. 18--Cash-short airlines scrutinizing the tiniest of details for increased efficiency have found that the familiar old "back-to-front" method of boarding a plane, starting with the rows farthest back, is just plain backward.
"The way we were doing it was probably the slowest way we could possibly do it," said Mark Ahasic, director of operational planning for JetBlue, the discount carrier.
But what should replace it?
America West uses the "reverse pyramid" method; Delta the "rotating zone;" and United the "window-middle-aisle" method. Each claims to shave precious minutes off the time an aircraft sits at the gate.
Jet Blue, which is introducing service to Pittsburgh at the end of the month, conducted trials on more than 100 actual flights as well as on a computer and found the method that was seemingly the most chaotic was the most efficient.
On a 156-seat plane, passengers boarding all at once, after the elderly and those needing special assistance, took 17 minutes to settle into their assigned seats, about a minute faster than any other method Jet Blue tried.
Jet Blue calls the method "random boarding" and switched to it systemwide in April. "It sounds worse than it is," Mr. Ahasic said. "It's all about simplicity. There's diffusion, and people disperse to wherever their row is, wherever their seats are."
Jet Blue said that, in airports that allow it to use both the front and the rear doors, it can board the plane in 13.5 minutes. In late May, Northwest changed from "front to back" boarding to random boarding, although it boards special assistance, first-class and elite-status passengers before the rest of the plane.
One reason beyond speed that appealed to both Jet Blue and Northwest was that the random method frees up boarding agents to do things other than announcing boarding groups every few minutes.
"From our point of view, it's less labor intensive," said Dean Breest, a spokesman for Northwest, which found that the system even worked well for jumbo jets. The only Northwest flights in the United States and Asia that do not use random boarding are its small commuter planes.
In the past year, United, AirTran and Northwest have changed their boarding procedures, with US Airways scheduled to change next year.
Airlines care about boarding speed because it affects "turn time," how long it takes to unload an airplane after its arrival at the gate and to prepare it for departure again.
"As long as [a plane] is sitting there on the ground, it's not generating any revenue," said David Swiegeria, president of AeroEcon, an airline consulting firm based in Vienna, Va.
Turn time involves maintenance, cleaning the plane and loading baggage, but passenger onloading and offloading usually accounts for whether the time is fast or slow.
Despite all the research, there's no consensus among the airlines on the best way to avoid bottlenecks among child-toting, luggage-lugging, aisle-blocking passengers.
Tim Lindemann, managing director of airport services for US Airways, has gone further than most in seeking an answer. In 2003, when he held the same position for America West, he commissioned a study by engineers at Arizona State University.
The researchers first conducted elaborate computer simulations that tried to minimize both "aisle interferences" (passengers toward the front of the plane blocking passengers trying to get to the back) and "seat interferences" (passengers in aisle seats getting up for passengers in window seats, blocking the aisle in the process).
The solution spit out by the computer was a "reverse pyramid" boarding process, essentially a combination of back-to-front and outside-in methods. The problems with the back- to-front method seemed to be the likelihood of aisle interferences and the fact that only a small portion of the plane was being filled at any one time.
After the reverse pyramid was tested on actual human beings and still seemed valid, America West put it into practice. Within three months of implementation, along with improved boarding pass designs, America West cut its average boarding time by two minutes and experienced a 21 percent decrease in flight delays, Mr. Lindemann said.
US Airways, which merged with America West last year, is testing the reverse pyramid on some flights and plans to implement it next year.
But while America West's experience has encouraged other airlines to examine their own procedures, it hasn't sold them on the reverse pyramid.
AirTran switched in July from back-to-front to a "rotating zone," where passengers board in sections that rotate from the back of the plane to the front.
In December, United announced it was switching to something it called WilMA, for "window-middle-aisle." At the time, United officials said the system would save four to five minutes per flight and $1 million a year.
And then there's Southwest, which always has divided passengers into groups according to arrival time and let them choose their own seats once they get on the plane.
While that system is regarded by most experts as the fastest, because people can just sit down if they want to avoid a bottleneck, it reportedly is the airline's chief source of customer complaints. Southwest is considering changing to assigned seating, and is developing technology to do so.
The confusion over the best system might stem from the fact that organizing airline passengers is, in some ways, like herding cats. When the Arizona State researchers switched from computer models to actually running tests and observing real passengers, they had a bit of a rude awakening.
Menkes van den Briel, the lead author of the study, describes passengers intentionally boarding in the wrong group, getting up and going to the bathroom after they were already seated, taking things out of carry-on bags that they had already stored and walking past their seats and having to "slalom" back through a clogged aisle. "It was hard to simulate," he said.
"FedEx has it very easy," Mr. Ahasic said of Jet Blue. "Packages don't talk."
Still unsolved is a good plan for quicker exits. Although they tend to be orderly, moving row by row from the front to the back, they involve long waits for passengers seated in the rear.
"That's a more difficult problem," said Mr. Lindemann, of US Airways, "because the passengers are entirely in charge of the process."
By David Bear and Anya Sostek