INTELLIGENT FLIGHT CONTROL has been tested in the mock cockpit (top) of the Advanced Concepts Flight Simulator (bottom) at the NASA Ames Research Center in California. Image: TOM TROWER NASA Ames Research Center
On July 19, 1989, as United Airlines flight 232 cruised over Iowa, the fan disk of the tail engine on the DC-10 broke apart, and the debris cut through all three of the plane's hydraulic lines. Because the pilots could not move any of the jet's control surfaces--the ailerons on the wings and the elevators and rudder on the tail--a horrific crash seemed inevitable. But by carefully adjusting power to the two remaining engines, the crew managed to maneuver the plane to the Sioux City airport. Although the jet flipped over and caught fire after hitting the runway, 184 of the 296 passengers and crew members survived.
The pilots of flight 232 proved that it was possible to control a modern airliner using only the engines. And this discovery led some innovative engineers to wonder if they could program flight computers to achieve the same feat, making it easier for a crew to safely land a heavily damaged aircraft. This research has been gradually progressing over the past 15 years, and the technology could be incorporated into commercial and military planes in the not too distant future. To judge how well these computer-controlled flight systems perform, I decided to see if they could enable a moderately experienced pilot like myself to fly a crippled jet.
This article was originally published with the title Crippled but Not Crashed.