Fly the Eco-Friendly Skies

A New Way to Fly

On my flight out to Seattle to research Boeing's advances, I pause as I leave the plane to ask the pilot if flying any differently could reduce the emission of greenhouse gases. He sets me straight. "It's not about greenhouse gases," he says. "It's all about fuel burn." From 2000 to 2007, the price of aviation fuel in the U.S. swelled by 115.6 percent, and fuel has topped labor as the number-one operating cost of the airline industry. Airlines, always concerned about fuel costs, are now obsessed with them. The nearest-term way airlines can reduce this expense (and reduce their greenhouse-gas emissions in the process) is to change how planes are flown.

Congestion in the air hurts fuel efficiency, just like on the ground. "On a good day, with nice weather, most airplanes fly efficiently," says Ian Waitz, director of the Partner program. "Things get challenging when you have congestion or weather problems. You have airplanes circling and sitting in taxi queues."

To mitigate congestion, the aviation industry is looking to adopt new flight patterns. In 2003, Congress created the Joint Planning and Development Office, which is building an entirely new air-traffic control system called NextGen, short for the Next Generation Air Transportation System. It's a huge overhaul expected to cost up to $22 billion.

One part of the project aims to land airplanes more efficiently. Now, to maintain safe spacing from each other, airplanes typically speed up and slow down repeatedly as they land, descending in steps and wasting fuel. But sophisticated computer models are under development that will carefully pace the landing of aircraft, allowing each to glide in practically on idle, a process called continuous descent approach. In a flight simulator, this method saved an average of 100 gallons of fuel on every approach to Los Angeles Airport.

Another NextGen initiative is to ditch the national radar system, which is based on World War II technology, and replace it with a GPS-based system called Automatic Dependence Surveillance Broadcast. Touted as the "backbone" of NextGen, ADS-B can precisely map an airplane's longitude, latitude, altitude and speed. The result will be more efficiently spaced airplanes flying faster on more direct routes. That saves fuel too. In 2005, NextGen reduced the mandatory vertical separation between airplanes at cruise altitude to 1,000 feet from 2,000 feet, a change that saves fuel by allowing more planes to fly at higher altitudes and avoid winds. The adjustment also opens up more lanes in the air, increasing airspace capacity by as much as 85 percent.

But NextGen is about increasing capacity, not cutting emissions. Although each flight may consume less fuel, the savings will be more than offset by the growth in traffic. "The whole point of [the program] is to develop the air-traffic system to allow the doubling of operations by 2025," Carl Burleson, director of the FAA's Office of Environment and Energy, tells me. "In the U.S. today, the issues blocking that growth are local air quality and noise. Greenhouse emissions haven't been a constraint."

Cleared for Landing : A prime goal of the NextGen air-traffic system now under development will be to eliminate the step-by-step descents that waste fuel. Currently, airplanes reduce altitude a little at a time to maintain safe separation between planes [A]. But future systems will allow planes to land practically on idle [B].  Kris Holland

The Light Option

Boeing's hangar in Everett, Washington, just north of Seattle, is the largest building in the world. One of the airplanes it houses is the most heralded commercial jet in years, the 787 Dreamliner, advertised as a "green" jet. But the plane is still behind closed doors—no visitors allowed—so I'm escorted into the office of Jeff Hawk, the Boeing Environment and Certification director who has worked on the 787 since 2002. He says that before the Dreamliner, Boeing had been planning to build a faster plane. He pulls out an off-white model of the original design, the Sonic Cruiser, which looks like a cousin to the Concorde. The Sonic Cruiser, streamlined like a barracuda, was to fly at the edge of the speed of sound.

"On a transatlantic flight, it would save about an hour or two," Hawk says. "It flew 20 percent faster but produced the same amount of fuel burn." The design concept crumbled when the airline industry was blindsided by the September 11 attacks in 2001. Passengers avoided the skies, and the industry lost $25 billion in just three years. Meanwhile, fuel prices crept upward and fuel efficiency became a top priority. Boeing decided to divert technologies being used to build a faster plane into building a more fuel-efficient one. Composite material planned for the Sonic Cruisers—carbon-fiber-reinforced plastic that's 70 percent the weight of aluminum—was carried over to the 787.

Engineers squeezed every efficiency they could from the airplane's classic shape. Among other tricks, they created a longer and thinner wing to generate more lift and less drag. As one part of the airplane became more fuel-efficient, so did the next. "If you have a low-drag airplane, you can use a much more efficient engine," Hawk explains. "That less-powerful engine is smaller. It's lighter too. A smaller engine means less drag. Instead of 20 percent faster, we were 20 percent more fuel-efficient." That efficiency has been a major selling point. Boeing has pre-sold 738 airplanes to 51 customers, making it the most successful release of a commercial jet in the company's history. It's also good for global warming, Boeing says, because 20 percent less fuel burn translates into 20 percent less greenhouse gas produced.

It sounds encouraging. But the 787 will replace other planes only gradually—Hawk estimates that Boeing will sell about 100 a year. He also acknowledges a more fundamental problem, which is that most jets aren't scrapped when new ones are bought, but rather sold, like used cars. "You can't just throw away a $50-million airplane."