A Cleaner, Leaner Jet Age Has Arrived
JET engines are now so reliable that a pilot can go an entire career without seeing one fail. Autopilots are so good that some airlines have set up their cockpits to emit a loud beep every few minutes, to make sure the crew is still awake. And navigation is so accurate that landings can be timed to the second.
Jet fuel is now the largest expense for most airlines, and for American carriers each penny increase in price per gallon costs nearly $200 million a year. The industry is also becoming increasingly nervous about what happens when that fuel is burned. Aviation is responsible for about 2 percent of global emissions of greenhouse gases, and that share will rise as air travel continues to grow.
So the industry is scrambling to build greener airplanes — to save weight and improve engine efficiency, with an eye toward reducing operating costs and emissions.
Pratt & Whitney, the engine company based in East Hartford, Conn., is testing an engine with gears arranged so that the fan in front turns at just one-third the speed of the blades in back. The innovation allows the use of a very big fan in the front, which will move more air at a slightly slower speed. “You can either make thrust by moving more air, or taking air and putting more fuel in it, to accelerate the air,” said Robert J. Saia, vice president of Pratt for new engine models.
Mitsubishi has selected the engine for its new regional jet, and All Nippon Airways has agreed to buy 15 of them. Bombardier, in Montreal, has listed the geared turbofan as a choice for a new line of regional jets it will build.
