HAA—Height Above Airport

HAR—High Altitude Redesign

HAT—Height Above Touchdown

HAZMAT—Hazardous Materials

HDD—Head-Down Display

HF—High Frequency

HGS—Head-up Guidance System

HIWAS—Hazardous In-flight Weather Advisory Service

HSI—Horizontal Situation Indicator

HUD—Head-up Display

IAF—Initial Approach Fix

IAP—Instrument Approach Procedure

IAS—Indicated Air Speed

ICAO—International Civil Aviation Organization

IF—Intermediate Fix

IFR—Instrument Flight Rules

IIMC—Inadvertent Instrument Meteorological Condition

ILS—Instrument Landing System

IMC—Instrument Meteorological Conditions