Definition
A series of unintended up-and-down (or other) oscillations of the airplane caused by the pilot's own control inputs, where each correction is applied out of phase with the airplane's motion and amplifies rather than dampens it. In landing, this typically appears as repeated nose-up/nose-down bouncing as the pilot chases the airplane's pitch attitude with the elevator.
Plain English
The airplane is bouncing or rocking, and the pilot's own control inputs — meant to fix it — are actually making it worse because each correction comes a moment too late and ends up adding to the next bounce.
Context Anchor
Seen in landing discussions, especially when a bounced landing or porpoise gets worse because the pilot keeps making control corrections at the wrong time.
Derivation
"Oscillation" comes from the Latin oscillare, meaning to swing back and forth. The phrase simply names where the swinging comes from: the pilot. The airplane is not unstable on its own — the pilot is the source of the back-and-forth motion.
Why Pilots Care
Pilot-induced oscillations can turn a minor bounce during landing into a loss of control, raising the risk of a hard landing or runway excursion.
Analogy
It is like overcorrecting a car that starts to drift in a lane: if each steering correction is too much and comes late, the car can start weaving back and forth instead of straightening out.
Grounding Statement
Picture the nose starting to rise after a bounce, the pilot pushing forward too late, then pulling back too late after the nose drops; each correction feeds the next motion.
Intuition Check
Pilot-induced does not mean the pilot is doing it on purpose. It means the pilot's corrections are causing or increasing the repeated motion.
Example Sentence 1
After the bounce, the student tried to push the nose down, then pulled back too hard, setting up pilot-induced oscillations down the runway.
Example Sentence 2
Recognizing the start of pilot-induced oscillations, the instructor told the student to relax pressure on the yoke and let the motion settle.