Definition
An instrument cross-check error in which the pilot applies, reduces, or holds engine power in a way that does not match what the current pitch and airspeed targets require, causing the aircraft to drift off the desired performance — usually altitude, airspeed, or rate of climb or descent.
Plain English
Using too much, too little, or the wrong amount of throttle for what you are trying to make the airplane do. The result is the airplane climbs, descends, speeds up, or slows down when you didn't want it to.
Context Anchor
Seen in instrument flying when a pilot is cross-checking the flight instruments and adjusting pitch and power to keep the airplane stable.
Why Pilots Care
Power and pitch work together to control altitude and airspeed. If power is set wrong, the pilot ends up chasing the airspeed and altitude indicators instead of holding a stable instrument scan. On instruments, this quickly leads to unstable flight and can mask other developing problems.
Intuition Check
Do not read power here as electrical power. In this context, power means engine output, usually controlled with the throttle. The mistake is not using power at all; the mistake is using it in a way that does not match what the airplane needs.
Example Sentence 1
The instructor pointed out that the student was improperly using power during level-offs, adding throttle too late and letting the airspeed decay below target.
Example Sentence 2
During the climb check the instructor noted the student was improperly using power to chase altitude rather than holding the correct pitch attitude.