Definition
Rapid, sudden movement of the throttle control to add or reduce engine power, rather than smooth, gradual application. In piston aircraft this can cause engine roughness, excessive cylinder wear, fuel-air mixture problems, and unwanted pitch and yaw changes; it is generally avoided in normal operations.
Plain English
Jamming the throttle in or yanking it out quickly instead of moving it smoothly. Pilots are taught to move the throttle gently because sudden changes are hard on the engine and make the airplane harder to control.
Context Anchor
Seen in instrument flying when discussing power control, airspeed control, and keeping the airplane steady without outside visual references.
Derivation
Abrupt' comes from the Latin abruptus, meaning 'broken off' or 'sudden.' It captures the idea of a movement that happens all at once rather than smoothly — exactly the kind of throttle handling pilots are trained to avoid.
Why Pilots Care
Can induce engine roughness, propeller stress, or momentary loss of control authority, especially when flying solely by reference to instruments.
Grounding Statement
A smooth throttle movement helps the airplane respond predictably; an abrupt one can make the airplane feel unsettled.
Intuition Check
Do not assume that faster throttle movement means better control. In instrument flying, smooth power changes usually give the pilot better control than abrupt ones.
Example Sentence 1
The instructor reminded the student that abrupt use of throttle during the approach was causing the airspeed to swing and making the glidepath harder to hold.
Example Sentence 2
Maintaining smooth power changes prevents the altitude excursions that often follow abrupt use of throttle in instrument conditions.