Development of an Independent Altitude Monitor Concept

The purposes of this study were fourfold: to examine the problems relating to inadvertent terrain strikes (altitude-related accidents) in the terminal area, determine requirements for an Independent Altitude Monitor (IAM), identify candidate concepts, and perform a technological appraisal of these concepts for possible development requirements. Study concepts were to consider a full range of aircraft and airport capabilities. Additionally, alert system concepts were reviewed for possible applications. Several existing and relatively short-term concepts were identified that offered significant IAM benefits. These covered altitude, path control, and improved position data, including altitude alert, minimum decision altitude alert, terrain proximity warning, ARTS III alert, visual aids, and distance-measuring equipment. Longer range development is necessary to satisfy all IAM requirements. Systems now under development offer basic elements of this capability.