Military and commercial aircraft designers are leading a quiet revolution in aviation, one of the most far-reaching since the Wright Brothers rose above the sandy soil of Kitty Hawk 100 years ago. Their goal is the all-electric aircraft, which would be controlled by small, computerized electric motors instead of today's heavy, maintenance-intensive hydraulic, pneumatic and mechanical systems.

The new technology has the potential to dramatically reduce per-passenger costs and ticket prices for commercial aircraft, while giving military planes more maneuverability and less vulnerability to enemy fire.

Aircraft designers already have reached a milestone -- installing "more-electric aircraft" technology in planes that will be unveiled over the next couple of years, such as the F-35 Joint Strike Fighter and the Airbus super-jumbo jetliner.

"A great deal has been achieved," said Richard T. Fingers, deputy director for propulsion technology at the U.S. Air Force Research Laboratory, at Wright Patterson Air Force Base in Dayton, Ohio.

An "all-electric" airplane would still rely on a fuel-burning jet engine for thrust. Most other systems would be electric, relieving demands on the engine.

"The engine, which is currently required to produce thrust, pneumatic power, hydraulic power and electric power, can now be redesigned and optimized to produce thrust and predominantly electric power," Michael Yates, an engineer with TRW Aeronautical Systems, wrote in a defense industry journal.

Joseph Weimer, chief of electric technology at the Air Force lab, estimated that the needed technologies may be ready by 2010. Meanwhile, the more-electric aircraft will bridge two eras in aircraft technology, as planes shed some of the traditional pneumatic and hydraulic systems for lighter, simpler, electric and electronic replacements.

Airbus Industries' new A380 super-jumbo jet will be the first commercial jetliner bearing the more-electric logo. The European consortium of French, German, Spanish and British aircraft companies hopes passengers will be flying in A380s by 2006.

The A380 will be the biggest commercial airliner ever built. Placed in Heinz Field, an A380 would stretch almost from goal line to goal line, with wing tips reaching beyond the sidelines. In its baseline configuration, it will be able to carry 555 passengers. "Stretch" and other variants will be able to hold nearly 1,000. A Boeing 747-400 jumbo jet carries about 416 passengers.

Early in the A380's design, engineers realized that a plane so gigantic would be impossible without more-electric technology.

Consider the problem of steering. In a conventional aircraft, pilots move control surfaces, such as the flaps in the wing and the vertical and horizontal stabilizers in the tail, by using hydraulic systems. Just as in a car's brake system, hydraulic lines magnify and transfer force through a fluid. Pressure exerted at the pilot's end of a hydraulic line is transferred to the other end, moving a control surface.

Because of its size, the A380 will have more flight control surfaces, and bigger surfaces than previous planes. A conventional hydraulics system capable of moving those surfaces would have been extremely heavy, reducing a plane's profitable payload of passengers and freight. So the A380 will use hybrid electric-hydraulic devices termed electrohydrostatic actuators. These self-contained units, located right where movement is needed, use a small electric motor to power a hydraulic piston. They have their own small reservoir of hydraulic fluid.

These actuators get commands electrically over a wire from the cockpit rather than through a hydraulic line, an approach sometimes termed power by wire. Wire is lighter than hydraulic lines, and it doesn't need fluid, valves or filters to remove contaminants. It doesn't leak, either.

Wire-based systems can be removed easily for repair or replacement. Removing hydraulic units requires draining hydraulic fluids, reconnecting fittings, refilling the system with fluids, bleeding to remove trapped air, checking for leaks in fittings and other steps.

Airbus estimates that more-electric technology will reduce the A380's weight to the point that it will be 20 percent more fuel-efficient than its smaller rival, the Boeing 747.

Safety also gets a boost, said Michael Comes, director of engineering systems for the A380, since a total loss of hydraulic power would still leave the hybrid controls operational.

The stealth F-35 fighter, being built by Lockheed Martin to replace existing fighters used by the Air Force, Navy and Marines, will use similar controls, although Fingers and other officials were reluctant to discuss details. Increased survivability is one reason. The hybrid actuators are self- contained and remotely located, eliminating the spider web of vulnerable hydraulic lines running through the fighter.

Reduced weight, maintenance and ground support are among the others.

When two dozen F-16s are deployed, for instance, it takes 16 C-141 cargo planes to haul the pneumatic gear needed to start their engines, various hydraulic fluid servicing devices and other support equipment. Hybrid electric-hydraulic systems could reduce that by 20 percent.