TAWSGPWS

TAWSGPWS, commonly referred to as TAWS or Enhanced GPWS (EGPWS), is an avionics safety system designed to prevent controlled flight into terrain (CFIT). It builds on the legacy Ground Proximity Warning System by adding a terrain database, more advanced terrain awareness, and predictive alerting to assist pilots in avoiding terrain and obstacles.

Operating principle: The system uses position information from navigation systems (GPS/GNSS or inertial reference), barometric altitude, radar altimeter data, and a digital terrain database. By comparing the aircraft's predicted trajectory to terrain elevations and obstacle data, TAWS can issue alerts well before the aircraft reaches dangerous terrain. Warnings are typically classified as cautions and warnings, accompanied by voice alerts and cockpit display indications.

History and standards: GPWS was introduced in the 1970s to reduce CFIT. In the 1990s, Enhanced GPWS, later called TAWS or EGPWS, added predictive terrain awareness and global terrain databases. Regulatory and industry standards were developed by ICAO and other aviation authorities, leading to widespread certification on commercial aircraft.

Operational considerations: TAWS relies on an up-to-date terrain database and reliable altitude information; its effectiveness depends on database currency and airplane operation within coverage. Limitations include potential false warnings in complex terrain, data integrity issues, and situations where the database does not reflect real-time changes.

Adoption and impact: TAWS/EGPWS is now standard on most commercial airliners and many business jets, with regulatory support and ongoing database updates designed to improve protection against CFIT.