GPS AND AVIATION SAFETY

A GPS-based autolanding and autonavigation system is one technology being looked at as a possible deterrent to future hijackers in the wake of the Sept. 11 attacks. Technologically feasible, at least one major maker of avionics is developing such an emergency landing system. The Federal Aviation Administration has two GPS-based systems, the Wide Area Augmentation System (WAAS), which steers aircraft to an approach, and the Local Area Augmentation System (LAAS), which guides them to a landing in zero visibility. Operational considerations include how and if to override the system, whether it could be jammed, and how much information to load in the database concerning runway availability and obstacles. A central challenge is modulating the threat an automatic system poses to the "cockpit philosophy" that makes the crew ultimately responsible for the plane's operation.