Aviation Acronyms

Aviation runs on abbreviations. This reference decodes the acronyms you will meet in manuals, cockpits, maintenance hangars and our articles on chipvortex.com. It is updated regularly — suggest an acronym if we are missing one.

A–C

Acronym Meaning In one line
AD Airworthiness Directive A mandatory fix or inspection ordered by the regulator.
ADS-B Automatic Dependent Surveillance–Broadcast Aircraft broadcast their GPS position for tracking.
AGL Above Ground Level Height measured from the terrain below, not sea level.
AMM Aircraft Maintenance Manual The manufacturer’s official maintenance procedures.
AOA Angle of Attack The wing’s angle to the oncoming air.
APU Auxiliary Power Unit Small tail-mounted turbine for ground power and engine start.
ATC Air Traffic Control Ground controllers who direct and separate traffic.
CG Centre of Gravity The balance point of the aircraft — it must stay within limits.
CVR Cockpit Voice Recorder Records cockpit audio for accident investigation.

E–G

Acronym Meaning In one line
ECAM Electronic Centralised Aircraft Monitor Airbus system that displays system status and failures.
EFIS Electronic Flight Instrument System The glass-cockpit displays replacing mechanical gauges.
EGT Exhaust Gas Temperature Key engine-health temperature measured in the exhaust.
EICAS Engine Indicating and Crew Alerting System Boeing’s equivalent of ECAM.
ETOPS Extended-range Twin-engine Operational Performance Standards Rules letting twin jets fly long over-water routes.
FADEC Full Authority Digital Engine Control The computer with total control over the engine.
FBW Fly-By-Wire Flight controls transmitted electronically instead of by cables.
FDR Flight Data Recorder The “black box” logging flight parameters.
FMS Flight Management System The navigation computer that flies the planned route.
FOD Foreign Object Debris/Damage Loose objects that can damage engines and tyres.
GPU Ground Power Unit External electrical power supplied at the gate.
GPWS Ground Proximity Warning System Warns pilots when terrain is dangerously close.

H–N

Acronym Meaning In one line
IAS Indicated Airspeed The speed shown on the airspeed indicator.
IFR Instrument Flight Rules Flying by instruments and ATC clearances, not by sight.
ILS Instrument Landing System Radio beams that guide aircraft to the runway in poor visibility.
ITT Interstage Turbine Temperature Turbine temperature reading on many turboprops and turbofans.
MEL Minimum Equipment List What may legally be inoperative and the aircraft still fly.
METAR Meteorological Aerodrome Report Coded routine airport weather report.
MRO Maintenance, Repair and Overhaul The industry (and facilities) that keep aircraft serviceable.
MTOW Maximum Takeoff Weight The heaviest the aircraft may legally be at brake release.
N1 / N2 Spool speeds Rotation speeds of the engine’s low- and high-pressure spools, in percent.
NDT Non-Destructive Testing Inspecting parts for cracks without damaging them.
NOTAM Notice to Air Missions Official notice of hazards or changes affecting flight.

P–V

Acronym Meaning In one line
PAPI Precision Approach Path Indicator Runway-side lights showing if you are on the correct glide path.
QRH Quick Reference Handbook The checklist book for abnormal and emergency procedures.
RAT Ram Air Turbine Emergency wind-driven generator that deploys if power is lost.
RVR Runway Visual Range How far down the runway a pilot can see.
SOP Standard Operating Procedure The airline’s standardised way of performing each task.
TAS True Airspeed Actual speed through the air mass, corrected for altitude and temperature.
TCAS Traffic Collision Avoidance System Onboard system that warns of, and resolves, mid-air conflicts.
V1 / VR / V2 Takeoff reference speeds Decision speed, rotation speed and takeoff safety speed.
VFR Visual Flight Rules Flying primarily by outside visual reference.
VOR VHF Omnidirectional Range Ground radio beacon used for navigation.

Last updated: August 7, 2026. Pair this with the Aircraft Glossary for full-word definitions.