Which periods constitute the critical phases of flight?

• A. First 5 minutes after takeoff, last 10 minutes before landing, and non-cruise flight under 10,000 ft.
• B. Only during takeoff and landing.
• C. During cruise at altitude.
• D. Non-cruise flight above 20,000 ft.

Answer: (A)

The periods considered critical are the times when the aircraft is operating closest to the ground and during high-power or high-workload phases, where firefighting response and safety concerns are greatest. Specifically, the first five minutes after takeoff, the last ten minutes before landing, and any non-cruise flight below 10,000 feet encompass the phases when the airplane is near the airport, undergoing configuration changes, and subject to potential go-arounds, aborts, or fuel-related hazards. These windows cover takeoff/climb, approach/landing, and the near-ground operations that demand heightened readiness for rescue and firefighting activities.

During cruise at altitude, the aircraft is distant from the airport, with stable performance and lower immediate risk around the airframe, so that period is not included. Similarly, non-cruise flight above 20,000 feet is still well above the airport environment and not considered a critical phase for on-ground firefighting operations.