Altering Planes, and the Way They Fly, to Save Fuel

Altering Planes, and the Way They Fly, to Save Fuel
CHRISTINE NEGRONI
Published: April 29, 2009
FOR the aviation industry, its fate inextricably linked to the price of oil, fuel conservation is more than environmentally sound — it’s a matter of survival. That is why, in research labs and in airline conference rooms, any measure is open for discussion if it reduces the use of fuel.

Todd Wade/American Airlines
UPLIFTING At the American Airlines maintenance base in Kansas City, mechanics secure a winglet to a jet’s wingtip. Winglets reduce drag and increase the amount of weight a plane can carry.

“Fuel economy and carbon emissions are exactly the same thing,” said Alan Epstein, vice president for technology and the environment at Pratt & Whitney, the jet engine manufacturer. “If you want to reduce carbon emissions, you reduce the fuel consumption.”

The most significant improvements come from broad changes in the way planes fly. Using global positioning information, airliners fly shorter, more direct routes to destinations rather than following rigid paths that can take them miles out of the way as they move from one ground-based radar beacon to another. Special landing procedures called continuous descent approaches let pilots reduce fuel to the engines to the idle setting as they begin their descent.

“The ultimate goal is to be able to push back, roll to the runway, take off and land and go to the gate, all without ever having to hit the brakes,” said Bob Smith, vice president of advanced technologies for Honeywell Aerospace in Phoenix. “If you can get that level of sophistication in the system, that’s a big deal.”

It’s a big deal because these kinds of operational changes affect an airline’s costs. In the past four years, fuel has surpassed labor as the airlines’ largest operating expense, so conservation efforts are bound to have an impact.

Environmental benefits are secondary but significant. In the United States, commercial aviation accounts for 2 percent of greenhouse gas emissions, according to the Air Transport Association, an industry group.

On a recent trial flight, Southwest Airlines used satellite navigation and continuous descent approaches on a round trip between Dallas and Houston and determined it could reduce fuel consumption by 6 percent.

“If we were able to reduce and get 6 percent savings across all our flights, that would equal 90 million gallons a year in fuel reduction and a reduction in carbon emissions of 1.9 billion pounds,” said Jeff Martin, Southwest’s senior director of flight operations.

Nancy Young, vice president of environmental affairs for the Air Transport Association, said that changing from a radar-based system to a satellite-based one was “a big, big thing.”

But incorporating the new flights into an older traffic infrastructure takes time. Air traffic control centers and airlines are in transition, with some updating equipment faster than others. According to the Federal Aviation Administration, about 80 percent of American airliners have the necessary devices.

Brian Will, program manager for American Airlines and a pilot, said the agency needed to do more to reward companies that make an investment in new technology. Air traffic control “is compelled to maintain a system that will accommodate everybody,” he said. “In my opinion, this is a mistake.”

The aviation authority is considering ways to expedite satellite-guided planes through the system. “Clearly there is a policy that we’re looking at right now to try and improve our delivery of services to those who are better equipped,” said Carl E. Burleson, the F.A.A.’s deputy acting administrator for policy planning and the environment.

If America’s air traffic infrastructure wasn’t so well established, it might be more nimble. Instead, less developed countries seem to be adapting faster, according to one industry expert.

“You’ll see this first in places like China; they’re leapfrogging a generation of technology,” said Ken Shapero, director of marketing communications for Naverus, an advanced navigation company in Kent, Wash. “But in the U.S., so much investment and infrastructure is in the old ways of doing things.”

Since fuel is consumed in the engine, manufacturers are eager to develop new models. Mr. Epstein of Pratt & Whitney said that 20 years ago, when jet fuel was less expensive, the company spent $1 billion inventing a gear to allow the engine fan to run at a slower speed than the turbine so that each part could work most effectively. That technology, called PurePower, had its first sale last month, when the Canadian aircraft maker Bombardier bought Pratt & Whitney’s engine for its CSeries airliners, which the company trumpets with the slogan “New Planet New Plane.”

Mr. Epstein said that when the work began, he didn’t know what its environmental impact would be. “We weren’t ahead thinking about carbon but we were thinking about fuel,” he said.

A plane’s design and the weight it carries also contribute to fuel consumption, which is why jetliners like the CSeries, Boeing 787 and Airbus A350 are being made from lighter-than-metal composite materials. Planes already in service are undergoing expensive modifications to take advantage of new knowledge about aerodynamic efficiency.

In Kansas City, Mo., mechanics at American Airlines are making an extensive after-market change to many planes in their fleet by installing 11-foot vertical panels called winglets on the wingtips of 58 long-range Boeing 767’s. The winglets reduce drag and increase the amount of weight the plane can carry by 12,000 pounds, increasing the profit-making potential of those flights.

Other airlines are adding winglets to their airplanes for a fuel savings that can be as much as half a million gallons per plane a year, said Patrick LaMoria, vice president of sales and marketing at Aviation Partners Boeing, in Seattle, the designer of the winglets. Winglets for the 767 can take a month to install and cost nearly $2 million per plane, he said.

Environmental concerns even extend to contrails, the white streams of condensation that trail the engine, as cooling exhaust gases freeze into ice crystals. These wispy clouds can remain in the atmosphere for up to eight hours, and studies have shown that they could be altering the earth’s temperature. On the list of priorities, contrails rank below anything else that saves fuel, money or greenhouse gas emissions.

“People are studying how to eliminate contrails,” Mr. Epstein said. “And if I could eliminate them for free I would, but if there’s a cost, particularly in carbon, you’d better understand the relative importance.”