What is a TLM file? A TLM file contains telemetry data recorded by an aircraft (e.g., planes) or spacecraft (e.g., satellites) in a binary format proprietary to the manufacturer of the craft. It may store various data, including scientific data recorded by measurement instruments, temperature readings from parts of the satellite or aircraft, or image data from the satellite or aircraft's cameras. Software available from the craft manufacturer allows users to display, analyze, and distribute the data.

More Information Since TLM files are created exclusively by aircraft and spacecraft, you will likely only encounter them in the aviation and aerospace industries. The Telemetry (TLM) format also supports an unlimited number of packet type and packet data sections, each representing logs written by the satellite or aircraft. Each section contains the open time, packet type, packet data, and close time. The times in TLM files are in Unix epoch time.