Definition
A condition in which the airplane's trim is not adjusted to relieve control pressures for the current flight attitude, airspeed, and power setting, requiring the pilot to hold continuous pressure on the controls to maintain the desired attitude.
Plain English
The airplane has not been balanced out so it flies hands-off at the chosen attitude. The pilot has to keep pushing or pulling on the controls to hold it where they want it.
Context Anchor
Encountered during instrument attitude flying, especially when changing power, airspeed, or configuration and then trying to hold a steady attitude by reference to the instruments.
Derivation
Trim' comes from the Old English 'trymman,' meaning to make firm, arrange, or set in order. In sailing, trimming meant adjusting sails so the vessel sailed steadily without constant correction. The aviation use carries the same idea: setting the airplane up so it flies steadily on its own.
Why Pilots Care
Causes extra workload, control pressure fatigue, and easy drift from altitude or airspeed during instrument flight.
Intuition Check
Do not read trim as decoration or neatness here. In flying, trim means adjusting the airplane so it does not keep trying to pitch, roll, or yaw away from the condition the pilot wants.
Example Sentence 1
The student's altitude kept drifting because of improper trim after the power reduction for descent.
Example Sentence 2
The student struggled to hold altitude until the instructor pointed out the improper trim was creating persistent nose-up pressure.