An ACMI file contains flight data recorded with Tacview, a flight analysis program. It stores information in plain text about the flight of a user and flights by AI units if they exist. ACMI files include all the flight information, which includes the speed, acceleration, orientation of the vehicle, recording and mission time, and the author, title, and category of the mission.

Tacview allows users to record flight data from real-world GPS data and flight simulators, such as X-Plane, Microsoft Flight Simulator, Lockheed Martin Prepar3D, IL-2 Sturmovik, and DCS World. The ACMI file is created by Tacview when a user saves the flight data from an imported simulator flight or real-life flight. Users can then share and re-open the files with Tacview to review flights for the purpose of improving their piloting skills. Since ACMI files can grow large in size, Tacview allows users to compress them with .ZIP compression to save storage space. Tacview allows users to choose the level of compression when they compress them and creates a file with the .zip.acmi file extension. NOTE: ACMI files are typically saved in the \My Documents\Tacview\ folder.