ABSTRACT
This chapter describes the generic name given to this type of protection: terrain awareness warning system (TAWS). The TAWS computing function can either be from a self-contained unit; alternatively, it can be integrated within another aircraft system. The TAWS computer function creates a four-dimensional position comprising: latitude, longitude, altitude and time. Cautionary alerts are given by TAWS that require immediate crew awareness; subsequent corrective action will normally be necessary. TAWS are specified in transport category aircraft as a result of mandatory rulemaking. The terrain awareness warning system comprises aircraft sensors, a computing function and warning outputs. Warning alerts are given for a terrain threat that requires immediate crew action. In addition to the terrain map, text messages are produced depending on system status and the terrain awareness threat level. First-generation ground proximity warning system technology used the radio altimeter to provide warning of terrain clearance.
