Plain English Meaning

The airplane is no longer at the altitude or airspeed the pilot planned for. It is higher, lower, faster, or slower than it should be — and that difference tells the pilot something about the airplane's energy that needs correcting.

Full Definition

Departures from the target altitude or target airspeed planned for a given phase of flight. In energy management, these deviations are observable signals that the airplane's total energy state, or the way energy is being distributed between height (potential) and speed (kinetic), no longer matches what the pilot intended.

Context Anchor

Seen during climbs, descents, , , and any time the pilot is checking whether the airplane is staying on the planned height and speed.