Definition 1 of 2
Definition
A pilot report classification for turbulence that causes rapid and somewhat rhythmic bumpiness without producing appreciable changes in aircraft altitude or attitude. Reported in two intensities: light chop (slight, rapid, somewhat rhythmic bumpiness without noticeable changes in altitude or attitude) and moderate chop (similar to light chop but of greater intensity, causing rapid bumps or jolts without noticeable changes in altitude or attitude).
Plain English
A type of turbulence that feels like a fast, steady bumpy ride, but the airplane keeps flying straight and level — the nose doesn't pitch around and the altitude doesn't move much.
Context Anchor
Seen or heard in weather reports and pilot reports, often with words like light, moderate, or severe to describe how strong the bumps are.
Derivation
From the everyday word 'chop,' meaning a quick, repeated motion — the same word used for 'choppy water.' The aviation use borrows that same idea: a steady, rapid bumpiness rather than a heaving roll.
Why Pilots Care
Helps pilots anticipate handling characteristics and decide on route or altitude changes for passenger comfort and safety.
Grounding Statement
In chop, the bumps come quickly, but the airplane is not being thrown far from its path.
Intuition Check
CHOP does not mean cutting something, reducing power, or making a sudden control input. In aviation weather, it means short, quick bumps in the air.
Example Sentence 1
Center, Cessna 32 Tango reporting moderate chop at one-zero thousand.
Example Sentence 2
We encountered moderate chop during descent through the cloud layer.