Which flight condition mandates use of the checklist?

The use of the checklist is crucial during critical phases of flight, particularly during takeoff and landing, because these phases represent the highest risk factors for any flight operation. During these times, pilots must ensure that all necessary procedures and safety protocols are followed meticulously to minimize the risk of error.

The checklist helps to confirm that all pre-flight actions have been completed, all necessary instruments are functioning, and that the aircraft is properly configured. This systematic approach is essential as it reduces the chances of overlooking important tasks or procedures that could jeopardize safety during these high-pressure moments.

When cruising at a stable altitude, while checklists may still be used, the chances of needing immediate corrective action are lower compared to the critical phases of flight. Similarly, while checklists can be beneficial during flight training exercises and during maintenance checks, the emphasis on their use is particularly strong during the more vulnerable moments of takeoff and landing. Thus, the answer appropriately highlights the importance of checklists in ensuring pilot preparedness and aircraft safety during the most critical times in a flight.