Atlas/ Glossary/ IM Abbreviation IM — ILS inner marker. IM ILS inner marker. Source 14 CFR § 1.2 → 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
