The Boeing 777 Does More With Less
My search for the perfect job has ended--I want to be the guy who cannons dead chickens into jet engines.
The job really exists. The chicken test is one of many trials jet engines must pass to be approved for use on commercial airliners. One such airliner, a Boeing 777, recently flew the skies over Fairbanks. The 777 was in Alaska this spring for cold-weather testing, even though it wasn't very chilly.
Before the Federal Aviation Administration approves a new engine model, the engines have to pass a number of tests in temperatures ranging from 40 below to hotter than 100 above. Temperatures near 50 degrees in the Interior were cold enough to perform the tests, said Hal Dufilho, a Boeing operations engineer. Dufilho gave me a lengthy tour in and around the royal blue British Airways prototype. Dozens of Boeing workers were climbing all over the aircraft to test out the two jet engines, which were General Electric models hanging on both wings like a pair of open-mouthed whales.
By flying "cycles," the engineers simulate two years of mechanical stress in just four months of testing. Cycles consist of starting the engine, taking off, climbing to altitude, cruising, descending, landing, and shutting down the engine. The Boeing crew's Fairbanks record is 19 cycles in one day.
The pilots for those flights must eat ice cubes for breakfast to deaden their nerves, because they purposely fly the 777 under what Dufilho described as "the worst possible conditions." For example, pilots simulate the loss of an engine by pulling one of the two engines back to idle speed during takeoff. The computerized brain of the 777 then takes over.
Sensing the loss of an engine, the computer adjusts the rudder (used to deflect air right or left and make the plane turn from side to side) to compensate for the missing engine thrust. The 777's computer does this faster than a human is able, Dufilho said. In an emergency, the pilot or co-pilot can override the system manually, just as a person driving a car with cruise control can take charge of the car by tapping the brake.
Climbing into the cockpit of the British Airways 777 is like entering a video arcade. The control panels facing the pilot and co-pilot feature liquid crystal displays in pastel shades of blue and purple. The only conventional indicator is a globe compass suspended in liquid. It sits between the pilot and co-pilot, where the rear-view mirror hangs on the windshield of a car.
The yokes, the pilot and co-pilot's "steering wheels," are different on the 777, Dufilho said. They transmit movement to different parts of the plane by electrical impulses rather than by conventional wire cables. When a pilot moves the yoke while flying a cable-controlled aircraft, he or she feels resistance. Because the 777 is electrically controlled, it can theoretically be steered as easily as a video game joystick. Since pilots are accustomed to steering systems that require a bit of muscle, Boeing installed tiny motors to provide false resistance to the yoke.
The 777's engines are impossible to ignore; they are the largest jet engines ever made, Dufilho said. The tallest NBA star can stand comfortably in the mouth of the engines, which yawn open in circles measuring 10 feet, 3 inches. A single engine has up to 110,000 pounds of thrust. With only two of these engines, the 777 has more thrust than the original four-engine 747, according to Boeing Maintenance Supervisor Bob McKee.
The engines, which consume over 1,900 gallons of fuel an hour, are powered by the action of 22 rotating fan blades. Tipped with titanium, the body of the fan blades are made of molded graphite fibers. The blades are so light and well-balanced that a light breeze at Fairbanks International Airport had them spinning like a house fan. It's into these fan blades that eight-pound dead chickens are freed from an air cannon. The test is performed to see how the blades react when the engine sucks in a large bird.
The official job title for this duty must be "Poultry Propulsion Specialist." Sign me up.
