By Jon Hilkevitch
Tribune Transportation Writer
August 4, 2000

DES MOINES -- With the closest airplane more than 40 miles from his Boeing 737, United Airlines Capt. Hank Krakowski skirted low-hanging storm clouds and still managed to shave three minutes off the 48-minute flight plan to Des Moines on one of the first experimental low-altitude flights from O'Hare International Airport.

Back in the passenger cabin, the flight attendants had just enough time to serve beverages and collect the cups.

By flying at a lower altitude, the airline expects it can get planes into the air quicker by avoiding the crowded lanes at higher levels, reducing flight delays. Yet the intent of the experiment was almost dashed during the Chicago-to-Des Moines flight: Though the plane pushed back from the gate on time, it spent 40 minutes waiting to take off, wasting hundreds of pounds of fuel, and ended up arriving 17 minutes late at its destination.

Although the short trip to Iowa this week, which a Tribune reporter observed from the third seat inside the cockpit, did not go as well as planned, the airline said taxiing times before departure have been cut by an average of 10 minutes on flights using the low-altitude routes.

In fact, the low-altitude flight fared better than most planes Monday, a day that saw average delays of 90 minutes, according to the Chicago Department of Aviation.

United, which this summer is suffering from one of the worst on-time arrival rates among the top 10 airlines, is the first carrier to operate the low-altitude flights out of O'Hare on trips of 500 miles or less. The airline is using the practice on about 50 flights a day. American Airlines is scheduled to begin similar service soon.

The idea is simple: Instead of delaying all departures when airline schedules outstrip the capacity in the highly congested commercial air lanes at 24,000 feet and above, United has opted for select destinations from Chicago to take advantage of the wide-open spaces between 18,000 and 23,000 feet.

United hopes the practice will cut the number of late flights at O'Hare, which suffered through 4,944 delays in June.

The planes burn more fuel because the resistance is greater flying through the thicker, low-altitude air.

But United and American anticipate the additional cost of about $400 per flight, mainly the result of higher fuel consumption, will be offset by significantly reducing the time that planes wait in line on the ground until a slot in the upper-altitude airspace is available all the way to their destinations.

In practice, however, the low-altitude flights are not shielded from the delay-inducing effects of poor weather, the limitations of the air-traffic system, long-distance flights that are granted preferential treatment for taking off and other complex issues that threaten to wrap the airline industry in gridlock.

The late departure this week of the Des Moines flight was due in part to a couple of 747s bound for Asia and a 777 headed to Europe, which were allowed by air-traffic controllers to cut into the takeoff line at O'Hare.

"The approximately 40-minute delay out of O'Hare was big enough to cost us an on-time arrival," said Krakowski, explaining that oceanic flights are given priority over puddle-jumpers such as the trip to Iowa because they have to arrive at designated points for the water crossings at specific times.

The economic and environmental impact of the severe delays at O'Hare becomes apparent by looking at airline fueling practices.

Flying a 737 at 20,000 feet to Des Moines from O'Hare burns 4,600 pounds of fuel--100 pounds more than if the aircraft were flying at the normally higher altitudes, according to United. But either way, United pumps an additional 3,800 pounds of fuel into each of its 737 jets serving the route to adjust for the lengthy ground delays at O'Hare.

The benefits of the low-altitude flights became apparent Monday while looking out a cockpit window through the raindrops at 20,000 feet. Overhead, storm clouds containing turbulent air grew in size, increasing the challenge for pilots to steer around the weather.

"The low-altitude flights are really a big plus during a thunderstorm," Krakowski said, "because the cloud tops pretty much stay where they are and leave a lot of navigable corridors for us on the lower flight paths."

The low-altitude routes, which the Federal Aviation Administration has been advocating for several years to reduce departure and airborne delays, have been used successfully by several other airlines since the spring at less-congested airports, such as those in Minneapolis, Detroit, Cincinnati and Cleveland.

United and American officials said they remain committed to trying the low-altitude paths on up to 100 flights a day from O'Hare to destinations within 500 miles, including Grand Rapids, Mich.; Indianapolis; Kansas City; Omaha; Rochester, Minn.; St. Louis; and Des Moines.

United last week started some low-altitude flights to Chicago from Toronto, which is beyond the 500-mile guideline, because those flights frequently had been arriving late and passengers were missing their connection at O'Hare to a non-stop flight to Hong Kong.

Officials said the low-flight program might be expanded to major airports even farther from Chicago.

"We've seen an immediate improvement," said Krakowski, who is also United's director of flight operations control. "When delay restrictions are placed on other Chicago-bound flights waiting for a spot in the high-altitude traffic streams, the low-altitude flights from Toronto have avoided getting stuck in the logjam. We're happy and so are our customers because it has solved the missed connections."

It may take some time, however, for the new procedure to become part of everyday practice.

An air-traffic controller at the FAA's Chicago Center in Aurora reflexively instructed the United plane en route to Des Moines Monday to climb to 23,000 feet in preparation for continuing on to a cruise altitude of 37,000 feet.

The flight's co-pilot, Roger Odell, radioed back that the plane was already cruising at 20,000 feet and would maintain that altitude until starting the descent into Des Moines.