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WASHINGTON — Pilots’ “automation addiction” has eroded their flying skills to the point that they sometimes do not know how to recover from stalls and other problems, pilots and safety officials say. The weakened skills have contributed to hundreds of deaths in crashes in the last five years, the officials say.
Some 51 “loss-of-control” accidents occurred in which planes stalled in flight or got into unusual positions from which pilots were unable to recover, making such accidents the most common types of airline mishaps, according to the International Air Transport Association.
“We’re seeing a new breed of accident with these state-of-the art planes,” said Rory Kay, an airline captain and co-chairman of a Federal Aviation Administration advisory committee on pilot training. “We’re forgetting how to fly.”
Chances for pilots to keep their flying proficiency by manually flying planes are becoming more limited, the FAA committee recently warned. Airlines and regulators discourage or even prohibit pilots from turning off the autopilot and flying planes themselves, the committee said.
Fatal airline accidents have decreased dramatically in the United States over the last decade. However, the Associated Press interviewed pilots, industry officials, and aviation safety experts who voiced concern about the implications of decreased opportunities for manual flight and reviewed more than a dozen loss-of-control accidents worldwide.
Safety experts say they’re seeing cases in which pilots who are suddenly confronted with a loss of computerized flight controls don’t appear to know how to respond immediately, or they make errors — sometimes fatally so.
A draft FAA study found pilots sometimes “abdicate too much responsibility to automated systems.”
Because these systems are so integrated in planes, one malfunctioning piece of equipment or a single bad computer instruction can morph into a series of other failures, unnerving pilots who have been trained to rely on the equipment.
The study looked at 46 accidents and major incidents, 734 voluntary reports by pilots and others, and data from more than 9,000 flights in which a safety official observed pilots.
It found that in more than 60 percent of accidents and 30 percent of major incidents, pilots had trouble flying the plane manually or made errors with automated flight controls.
A typical mistake was not recognizing that either the autopilot or the auto-throttle — which controls power to the engines — had disconnected. Others failed to take the proper steps to recover from a stall in flight or to monitor and maintain airspeed.
In the most recent fatal airline crash in the United States, in 2009 near Buffalo, the co-pilot of a regional airliner programmed incorrect data into the plane’s computers, causing it to slow to an unsafe speed.
That triggered a stall warning. The startled captain, who hadn’t noticed the plane had slowed too much, responded by repeatedly pulling back on the control yoke, overriding two safety systems. The correct procedure was to push forward.
An investigation later found no mechanical or structural problems would have prevented the plane from flying if the captain had responded correctly. Instead, his actions caused an aerodynamic stall. The plane plummeted, killing all 49 people aboard and one on the ground.
Two weeks after the New York accident, a Turkish Airlines Boeing 737 crashed into a field while trying to land in Amsterdam. Nine people were killed and 120 injured. An investigation found that one of the plane’s altimeters, which measures altitude, had fed incorrect data information to the plane’s computers.
That, in turn, caused the auto-throttle to reduce speed to a dangerously slow level so that the plane lost lift and stalled. Dutch investigators described the flight’s three pilots’ “automation surprise” when they discovered the plane was about to stall. They hadn’t been closely monitoring the airspeed.
In such cases, the pilots and the technology are failing together, said former US Airways Capt. Chesley “Sully” Sullenberger, whose precision flying is credited with saving all 155 people aboard an Airbus A320 after it lost power in a collision with Canada geese shortly after takeoff from New York’s LaGuardia Airport two years ago.
“If we only look at the pilots — the human factor — then we are ignoring other important factors,” he said. “We have to look at how they work together.”
The ability of pilots to respond to the unexpected loss or malfunction of automated aircraft systems “is the big issue that we can no longer hide from in aviation,” Bill Voss, president of the Flight Safety Foundation in Alexandria, Va., said.
The foundation, which is industry-supported, promotes aviation safety worldwide.
Airlines are seeing smaller incidents in which pilots waste precious time trying to restart the autopilot or fix other automated systems when what they should be doing is “grasping the controls and flying the airplane,” Bob Coffman, another FAA pilot training committee member and a captain, said.
Paul Railsback, operations chief at the Air Transport Association, which represents airlines, said, “We want to encourage pilots to do that and not rely 100 percent on the automation In May, the FAA proposed requiring airlines to train pilots on how to recover from a stall, as well as expose them to more realistic problem scenarios.
But other regulations are going in the opposite direction. Today, pilots must use their autopilot when flying at altitudes above 24,000 feet, which is where airliners spend much of their time cruising. The required minimum vertical safety buffer between planes has been reduced from 2,000 feet to 1,000 feet. That means more planes flying closer together, necessitating the kind of precision flying more reliably produced by automation than humans.
Airlines tell their pilots to switch on the autopilot about a minute and a half after takeoff, when the plane reaches about 1,000 feet, Mr. Coffman said. The autopilot doesn’t go off until about a minute and a half before landing, he said.
Mr. Voss said airlines will have to rethink their operations if they’re going to give pilots realistic chances to keep their skills honed, he said.