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The Next Jet Set
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Shoulder-launched missiles home in on heat generated by airplane engines, so military planes use devices that employ flares, lasers, or infrared lamps to confound the missiles' guidance systems. But flares would not be appropriate for commercial jets because they start fires when they land on combustible materials. A more suitable system, called Directional Infrared Countermeasure (DIRCM), sends modulated beams of light, made by flashlamps or lasers, to fill the missile's guidance system with "false" data, deceiving or jamming the missile and causing it to miss. Northrop Grunman's Nemesis, a flashlamp-based DIRCM, is currently being used on military aircraft including the C-130, a military transport vehicle.
Busier but Safer Skies
The challenge of the airlines and air-safety organizations over the next few decades will be to drive down accident rates even as more planes take to the air. One safety innovation that has helped prevent crashes is "fly-by-wire" technology, a system in which a computer processes the pilot's control movements and sends electric signals to move the plane's control surface (such as wings and flaps) without any mechanical linkage.
In large aircraft using a conventional system, the pilot's input is transmitted in a way that is similar to automotive power steering, using hydraulic forces; there still is a direct relationship between the pilot's inputs and the control surface. In modern fly-by-wire systems, the pilot's control inputs are fed to a computer that decides which control surfaces to operate, and by how much.
The first fly-by-wire civilian airliner was the Concorde, although it used an analogue system to minimize weight. The Airbus A320 in 1988 was the first commercial aircraft to use digital fly-by-wire, and the system is now found in many modern large commercial planes. In addition to reducing the weight of the aircraft, digital fly-by-wire can enhance safety through the use of 'hard protection,' which monitors the pilot's commands to ensure the plane is kept within a safety margin. For example, if the pilot pulls back suddenly on the control stick to avoid another plane, the system can automatically limit the angle of the climb to keep the plane from stalling and falling out of the sky. The idea is that the computers can protect against pilot error.
Innovations like fly-by-wire will be sorely needed as skies grow even more crowded. Boeing estimates that over the next 20 years, air travel will grow by more than five percent annually, as measured in "Revenue passenger-kilometers" (RPKs -- the number of passengers multiplied by the number of kilometers they fly). In 1997, a Boeing analysis projected that if airline traffic growth continued at its present pace without reductions in the accident rate, by 2015 there would be a commercial plane crash somewhere in the world roughly once a week.
Such an unsettling scenario is unlikely as new safety features continue to be developed, and flying will most likely maintain its status as the safest way to travel. With careful planning and further innovation, the extra air traffic may be absorbed without reducing safety, and hopping on planes like the A380 or the Dreamliner will become the new routine for the next generation of travelers.
Jim Stallard is a New York-based science and humor writer who has been published in SCIENCE Online, MCSWEENEY'S, MODERN HUMORIST, SWEET FANCY MOSES, and MIGHT magazine.
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A simulation of TWA Flight 800, which crashed off of Long Island, New York in 1996. |
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