What does a level 3 warning necessitate from the crew?

A level 3 warning requires immediate action from the crew because it indicates a critical situation that poses a direct threat to safety or operational integrity. This could involve significant risks such as potential system failures, imminent collisions, or severe flight path deviations requiring the crew to take prompt corrective measures. The emphasis on immediate action reflects the urgency associated with level 3 warnings; crew members must quickly assess the situation and execute prescribed emergency procedures or mitigations to ensure safety. The effectiveness of the response during such a critical event is vital for the safety of both the aircraft and its passengers.