Terrain awareness alerting and display functions must be inhibited within which phases and within what distance of an airport not contained in the EGPWS airport database?

• A. Takeoff, Approach, and Landing
• B. Cruise, Descent, and Climb
• C. Taxi, Takeoff, and Landing
• D. Approach, Climb, and Descent

Answer: (A)

Terrain awareness alerting and display functions are restricted when the aircraft is operating close to the ground during the most hands-on phases of flight, and especially near airports that aren’t in the EGPWS airport database. During takeoff, approach, and landing, the system is inhibited to avoid nuisance or unreliable warnings when the runway and surrounding airport data aren’t fully loaded or validated in the database. Additionally, there’s a defined radius around such airports (typically about 40 nautical miles) within which TAWS is inhibited, because terrain data in that region may not accurately reflect the actual environment. Outside these phases and outside that radius, TAWS alerts operate normally, providing terrain warnings as you fly.