When could the low energy SPEED, SPEED, SPEED warning be triggered?

The low energy SPEED, SPEED, SPEED warning is designed to alert the pilots that the aircraft does not have enough energy to maintain a climb using pitch alone. This situation typically arises during critical phases of flight when the aircraft is not generating sufficient lift or thrust to sustain a positive rate of climb.

When the airplane's energy is insufficient, it can lead to a loss of altitude or a failure to climb, which can compromise safety. The system monitors various parameters, including airspeed, angle of attack, and aircraft configuration, to determine if the energy state is within acceptable limits. Therefore, the triggering of this warning indicates that corrective actions may be necessary to recover or maintain a safe flight path.

In terms of the other options, selecting TO/GA thrust may provide necessary thrust but does not define the conditions under which the warning is triggered. The cruise phase typically allows for stable flight with sufficient energy, and alternate law refers to a backup mode that does not inherently relate to the trigger condition of the warning. Thus, these aspects do not encompass the requisite flight dynamics leading to the low energy alert.