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The Prime-Time Crunch Causes Delays in Flights

March 08, 1987|PETER S. GREENBERG | Greenberg is a Los Angeles free-lance writer.

Last year, flight delays rose 23% above 1985 levels. Delays of more than 15 minutes surged more than 20% at the 22 busiest U.S. airports. (There were an average of 1,144 flight delays every day in 1986.)

The first problem is one of scheduling and competition among airlines on popular routes.

Here's a look at classic arrival delays that happen almost daily:

O'Hare Airport. 9 to 9:30 a.m. Most airlines that fly to Chicago have a plane scheduled to land there within this 30-minute period.

In the first half-hour there are 63 scheduled arrivals, and 49 of those are scheduled between 9:15 and 9:30. According to individual airline schedules, 36 arrivals are scheduled at 9:15 . . . a physical impossibility.

Even if you assume that all airlines going into O'Hare could operate on two separate runways, if your plane is scheduled to land at 9:15 it still means you stand only a 1-in-18 chance of landing on time in Chicago.

Given the odds, is it still possible to fly to Chicago and land on time at O'Hare around 9 in the morning?

Wayne Dimmic, an air traffic controller based in St. Charles, Mo., says the answer is a qualified yes. He publishes the Peak Delay Guide, a monthly list of each airline's flights to and from major U.S. airports, including expected arrival and departure delays.

"Our figures show that if you can get on a plane that lands in Chicago before 9:15 in the morning," he said, "you should make it with a very light delay factor."

Some Dimmic flight comparisons: United Airlines Flight 1 leaves Newark Airport at 7:30 a.m. and arrives at O'Hare at 8:52 a.m. According to Dimmic's statistics, the flight will experience an eight-minute delay in good weather and a 15-minute delay in bad weather.

One Without Delay

A little while later, UAL Flight 951 leaves White Plains, N.Y., at 7:50 a.m., and is scheduled to arrive at O'Hare at 9:11.

"According to our stats," Dimmic said, "he receives virtually no delay, regardless of weather in the air."

The crunch comes for planes arriving a little later. United Flight 63 and American Flight 553 both depart from La Guardia at 8 a.m. and are scheduled to arrive at O'Hare at 9:25.

Reasonable Odds

"Under good weather conditions," Dimmic said, "we show a 27-minute delay. Poor weather conditions gives these flights a 43-minute delay."

Dimmic's statistics don't--and can't--cover unscheduled mechanical delays, weather problems on the ground or baggage loading problems.

"We're just trying to give folks the reasonable odds of getting where they're going on time, based on what the air traffic system can handle."

Denver arrivals are also a major problem. If, for example, you need to leave Colorado Springs in the morning and fly to Denver in time to make a flight connection to anywhere else, chances are good that you'll miss the connection, Dimmic said.

The exception is Continental Flight 3321, which departs Colorado Springs at 7:15 and is scheduled to arrive in Denver at 7:50. Dimmic's report: no delay.

Half an hour later, things get worse. United Flight 3702 leaves Colorado Springs at 7:45 and is scheduled to arrive in Denver at 8:15. In good weather, the flight has a 13-minute delay; poor weather extends that delay to 28 minutes.

Continental Flight 419 is scheduled to leave Colorado Springs five minutes later, at 7:50, and arrive at 8:20. That extra five minutes could make a big difference. In good weather, Dimmic's stats indicate a 24-minute delay; in bad weather, 50 minutes.

Day's Busiest Hour

The reason: The 8 a.m. hour in Denver is one of the busiest of the day, with 70 arrivals for that hour. Twenty-three are scheduled to arrive between 8 and 8:15. Forty flights are due in between 8:15 and 8:30. The big crunch comes when 16 flights show up, all scheduled to land at 8:10. (If you're on one of those flights, you have a 2-in-16 chance of being on time, if both parallel runways in Denver are in use.)

At O'Hare, 91 departures are scheduled between 6 and 7 each evening. Forty-nine of those head west, and 42 of them leave between 6:30 and 6:45 p.m.

If you depart on American Flight 185 at 6:39 for Los Angeles (scheduled to arrive at 8:39), Dimmic predicts a departure delay of between six and eight minutes. Not too bad.

Five minutes later, American Flight 599 leaves at 6:44 for Long Beach with a scheduled arrival at 8:56. However, it receives a 20-minute departure delay.

Chain Reaction of Delays

"The problem with this flight is the exact minute that it's leaving," Dimmic said. "At 6:39 there are nine departures. At 6:40 there are 14 departures, and the spillover effect of those delays affects the 12 departures scheduled at 6:44, not to mention the 11 departures scheduled at 6:45. The first airplane that gets out at 6:39 has no problem. Everyone else has a problem."

Many solutions have been proposed to lessen delays. Unfortunately, few solutions have ever been implemented to deal with the problem of wait reduction.

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