| Abbreviation | Definition |
|---|---|
| ACS | Airmen Certification Standards |
| ACS | ARINC 664 network cabinet switch |
| ACSA | Airports Company South Africa |
| ACSC | Air Conditioning System Controller |
| ACSEP | Aircraft Certification Services Evaluation Program |
| ACSEP | Aircraft Certification Systems Evaluation Program |
| ACT | Actuator |
| ACTSI | Aviation Concepts Technical Services Inc |
| ACU | Air Cooling Unit |
| ACU | Antenna control unit |
| ACW | Aircraft Control Warning |
| AD | Aerodrome |
| AD | Airport Discharge |
| AD | Airworthiness Directive |
| ADA | ADvisory Airspace |
| ADAG | Aircraft Design and AeroflightDynamics Group |
| ADAP | Aircraft Deicing / Anti- Icing Program |
| ADAT | Abu Dhabi Aircraft Technologies |
| ADB | Area distribution box |
| ADB | Audio distribution box |