Projected flight path displays and controlled flight into terrain accidents

In the early 1980's aircraft were introduced with automated "glass cockpit" displays that present computer processed airplane systems and navigation information. Today such displays have become standard equipment on nearly all recently manufactured air transport turbojets, irrespective of the airframe manufacturer or flight management computer designer. Among their numerous capabilities, these displays can portray navigation information in a readily interpretable manner and project the airplane's future lateral flight path with reference to critical navigation aids and areas of hazardous weather. As a result, pilots of these aircraft can quickly process navigation information and maintain a considerably enhanced awareness of their airplane's position as compared to pilots of analog-equipped aircraft. However, even with these capabilities several glass cockpit equipped aircraft have been involved in controlled flight into terrain accidents, in which the airplanes struck terrain following the pilots' failure to recognize their proximity to that terrain. Despite the considerable superiority of the presentation of position information in glass cockpit aircraft relative to older aircraft, these accidents demonstrate that under certain conditions pilots of such aircraft can still lose their position awareness. This paper examines three controlled flight into terrain accidents involving airplanes equipped with glass cockpit projected flight path displays, to determine commonalties among the errors that the pilots committed and limitations in the displays that may have contributed to those errors.