NASA's simulator seeks air safety clues

My grip tighted on the jetliner's controls. Through the cockpit window, the lights of the twin runways of San Francisco International Airport rushed forward out of the twilight.

''Pull the nose up, about now,'' instructed David Weise, sitting beside me in the left seat of the cockpit. The stick bucked a little as I pulled it toward my chest.

Dials spun. The lights marking the end of the runway sped past and gradually slowed.

To my surprise - and relief - I had just safely landed a commercial 727 jetliner, despite the fact that I am a total novice. (My predecessor bounced the aircraft three times before reaching the end of the runway.)

Actually, during my ''flight'' around San Francisco Bay, we never left the ground. In fact, we never left a large boxlike structure that is one of the most sophisticated flight simulators yet built.

This machine, which Mr. Weise manages, is a key part of a new $12 million National Aeronautics and Space Administration (NASA) facility dedicated this week here at the Ames Research Center. Called the Man-Vehicle Systems Research Facility, its purpose is to study the role of human error in aircraft accidents.

''Air travel is one of the safest forms of transportation. But of the accidents which do occur in commercial aviation, about 65 to 70 percent are due to human error. But I see no reason why we can't nearly eliminate human errors once we understand why they occur,'' says John K. Lauber, chief of NASA's Aeronautical Human Factors Research Office.

To aid in this effort, the new NASA flight simulator has all the capability of those currently used by airlines for training, plus a number of additional features.

In common with conventional models, the NASA simulator is mounted on hydraulic pistons that allow itto roll, pitch, yaw, and vibrate like a real airliner. The sounds of an aircraft are duplicated, down to the drumming of raindrops when flying through a squall. A sophisticated computer system simulates the patterns of lights that pilots see while flying from dusk to dawn.

The additional realism of this simulator comes from the fact that its visual system produces the lights and images of up to 36 other aircraft. In ordinary simulators, pilots have the computer-generated sky all to themselves.

In addition, the new facility has a simulated traffic-control center designed by scientists at the Massachusetts Institute of Technology. This provides pilots with an extremely realistic radio link with ground control.

''This is the most detailed of any of the simulations I've experienced,'' says T.R. White, a pilot on furlough from United Airlines. He is working with the Link Flight Simulator Division of Singer Company, which is managing the facility for NASA.

In the demonstration flight given to visiting journalists, the flight simulator remained stationary. The only suggestions of motion came from recorded sound and the movement of images in the cockpit windows. Yet the illusion was strong, at times almost overpowering.

When the facility goes into full operation, flight crews from major airlines will be involved in the testing. In the simulator, they will go through the same actions they perform during a real flight.

While they do, researchers will record their conversation, their behavior, and reactions right down to their eye movements in an attempt to understand the conditions that cause even highly trained crews to make mistakes.

Past studies have shown that airliner crews make small mistakes frequently, Dr. Lauber explains. But there are so many checks and balances built into the system that these mistakes are normally caught and corrected before they cause any problem.

''Generally, it takes a succession of mistakes, several of them serious, to create an accident,'' he says.

The most dangerous type of error, Lauber argues, is the breakdown of information management: ''These days there's a great deal more to being a pilot than stick and rudder skills.''

The classic example of this problem was the 1974 crash of a jumbo jet in the Florida Everglades.

On approach to Miami, the pilot lowered the landing gear, but the green light indicating that the wheels were properly down did not flash on. So they circled on autopilot as they tried to figure out what the problem was. No one noticed until too late that the autopilot had been accidentally disengaged, and the plane crashed.

''What the captain should have done was take charge of the situation. Tell the copilot to fly the plane. Tell the engineer to check the light. While he kept in touch with traffic control. But, at the time, no one was training pilots in this sort of management,'' Lauber explains.

But five years ago when NASA researchers identified this as a serious problem , they held a special workshop attended by a number of airline representatives. As a result, a number of airlines have now adopted training programs specifically on this subject, Lauber reports.

One of the first subjects the new center will study is the effect of fatigue and jet-lag on pilots, and methods to counteract them. Another investigation will be to study how a number of actual flight crews communicate and interact. The simulator also will be used to test the effectiveness of various alert and warning systems.

Besides the 727 mockup, a simulator designed like the cockpit of an aircraft of the type that experts think will be flying in 1995 is also being completed.

The latter replaces dials and gauges with computer display screens, keyboard, and a computer that responds to spoken commands. A joint project with the Lockheed-Georgia Company, this Advanced Concepts Flight Simulator will allow scientists to study the safety and effectiveness of futuristic aircraft control systems.

''I'm not convinced we're smart enough yet to apply this new technology correctly,'' says Dr. Lauber. The current trend is to make people into passive monitors. But people aren't good at this. Already, accidents are appearing that seem to come from this approach, he says.

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