- AC
- Advisory Circular, such as AC-152 which enforces DO-254 for "custom microcoded devices"
- AC 20-152
- The Advisory Circular dated 6/30/05 that mandated the use of DO254 on PLD/FPGA/ASIC components.
- ACO
- Aircraft Certification Office, a local office of the FAA that assists with design approval and certificate management; US production approvals; engineering and analysis questions; investigating and reporting aircraft accidents, incidents, and service difficulties; DER oversight.
- AIR
- AIRcraft certification service. There are various divisions of the FAA, such as AIR 120 and AIR 200, which are all involved in various aspects of aircraft certification.
- AMOC
- Acceptable Means of Compliance, for example, code coverage is an AMOC for verification metrics
- AOPA
- Aircraft Operators and Pilots Association
- ARINC
- Aeronautical Radio Incorporated, a company that is the leading provider of transportation communications and systems engineering solutions for five major industries: aviation, airports, defense, government, and transportation, also synonymous with various ARINC parts such as the ARINC 429, a two-wire data bus that is application-specific for commercial and transport aircraft.
- ARP
- Aerospace Recommended Practice, for example ARP 5754 "Guidance for Development Validation and Verification of Complex Aircraft Systems"
- CAST
- Certification Authorities Software Team, an international group of participants from worldwide aviation certification authorities including the FAA, despite the name this group discusses complex electronic hardware issues also
- CEH
- Complex Electronic Hardware, for the context of DO-254, this means custom microcoded devices (PLD, FPGA, ASIC)
- CFAR
- Code of Federal Aviation Regulations
- CFR
- Code of Federal Regulations, such as CFR �� 183.29, which defines criteria for DERs
- CRI
- Certification Review Item, as per EASA. Pronounced "Kree", these are requirements above and beyond DO-254/ED-80, such as the CRIs for the Airbus 380 or A400M projects