Making Cockpit Automation More Pilot-Friendly
Two Northwest Airlines pilots caused a nationwide stir last fall when they became so engrossed in discussion that they ignored cockpit alerts and calls from air-traffic controllers, overshooting the Minneapolis airport by 150 miles. Dr. David Kaber, a professor in NC State's Edward P. Fitts Department of Industrial and Systems Engineering, says such cockpit complacency has occurred more frequently as aircraft controls have become more automated. He's been working on a three-year study for NASA Ames Research Center to determine what factors cause performance problems for pilots so manufacturers can better design next-generation avionics.
Sometimes, pilots are "out of the loop" as to what aspects of flying they need to monitor because automated flight controls are so reliable.
Some flight management systems contain up to 17 levels of automation to set an aircraft's trajectory and air speed at various points of a flight. Kaber says that sometimes leaves pilots "out of the loop" as to what aspects of flying they still need to monitor. "The automation is so reliable that there can be a loss of situational awareness," he says. On the other hand, he says, low levels of automation force pilots to remember more items, make quick calculations, and manually input flight-control data, leaving them little time to make critical decisions, possibly leading to errors. "It's definitely a two-edged sword," Kaber says. "It's very pilot-specific as to how much automation is too much or too little."
The issue becomes more vital as the Federal Aviation Administration develops a next-generation system that will cut the distance between planes during takeoffs and landings to improve the flow of air traffic. Under the new system, pilots will receive clearance earlier to make straight-line descents into airports instead of the current stair-step method. Kaber's research team tested pilots to determine whether they could reset the flight management system within a specified time to perform a straight-line descent.
To create a model of pilot behavior, the researchers videotaped a former military pilot operating a flight simulator. He described what he did and why he made certain decisions at particular junctures. The team then brought in commercial pilots to validate the model, having the pilots and the model run the same flight scenario. Both the simulations and the model showed that the automated system for straight-line descents needs further development. "Pilots can't make effective decisions fast enough with current automation," Kaber says. The computer model will allow the FAA and manufacturers to refine the automation without the time and expense of having commercial pilots test it in a simulator, he says. "We can now predict problems with flight management systems in advance and design systems that will be safer."