Atlas/ Glossary/ CHOP Abbreviation CHOP — - A form of turbulence. CHOP - A form of turbulence. Source FAA Pilot/Controller Glossary → Related — Abbreviation. ABEAM ABEAM ABORT ABORT — To terminate a preplanned aircraft maneuver AFM AFM — airplane flight manual AGL AGL — above ground level ALS ALS — approach light system APU APU — auxiliary power unit