Plain English Meaning

Letting the airplane end up with the wrong combination of height, speed, and power for what you're trying to do — for example, too high and too fast on final, or too low and too slow on a go-around.

Full Definition

A failure to properly control the airplane's total energy state — the combination of altitude (potential energy), airspeed (kinetic energy), and engine power (chemical energy being converted to thrust) — resulting in too much or too little energy for the current phase of flight. Mismanagement of energy is a leading causal factor in loss-of-control accidents, excursions, , and unstabilized .