Air Transport World

Of men and machines; human-factors analysis is enjoying increased emphasis in aviation. And not only in the cockpit.

When Wilbur and Orville Wright demonstrated the latest versions of their flying machine to crowds in Europe and the U.S. in 1908, one of the most noticeable changes was in the position of the pilot: He was seated. In their earlier craft, the pilot lay prone on the lower wing, with elbows pressed forward to help keep his head elevated. That was acceptable for flights measured in seconds but with experience and design changes, flights grew longer and a pilot could not endure these with his spine bent backward, the Wrights learned.

The two early aeronautical engineers would not have recognized the term but in reconfiguring the pilot's position, they had applied human-factors analysis to their design.

Human factors is the science of enabling the human and mechanical components in a system to work well together. In the realm of flight, that means allowing for human capabilities and limitations in design and operation of aircraft.

Certainly, human factors, as the Wright Brothers demonstrated, is not new. But it is enjoying increased emphasis. Under the Human Factors Plan begun two years ago, FAA will spend $22.9 million this year on research in the area, with higher levels planned for the years to follow.

In aviation, human factors is associated most commonly with cockpit design--for example, the effect of the glass cockpit on pilot workload or whether the Airbus A320's side-stick controller is preferable to the traditional center column and wheel.

But human factors has an impact on more than just the way metal is bent around two or more pilots. It!s a consideration of the methods by which they do their jobs, as well. And it also extends outside the cockpit, to a surprising number of other areas in airline operations. What follows, then, is a glimpse at a few of the less recognized applications of human factors. Maintenance. Human-factors specialists dis. covered airline mechanics fairly recently. Accidents such as those involving the United DC10 at Sioux City, Iowa and the Aloha 737 in 1988 showed that maintenance failures can wreak havoc as surely as piloting errors can. One way to prevent such faflures is to improve training methods and FAA has a program to do just that. Another way is to keep the mechanic in mind as the aircraft is designed.

"There's a tremendous amount of expertise and methodology for cockpits but not for maintenance," says Jack Hessburg, chief mechanic for Boeing's 777 program. …

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