FAR 21.611 — TSO Authorization Issuance
FAR 21.611 explains how the FAA issues a TSO authorization, including any granted deviations, once an applicant meets subchapter requirements.
FAR 21.611 is a short but important rule in the Technical Standard Order (TSO) approval process. A TSO is a minimum performance standard the FAA sets for specified materials, parts, and appliances used on civil aircraft (think things like seat belts, GPS units, or emergency locator transmitters).
Under this section, once the FAA reviews an application and determines the applicant has met all the requirements of the subchapter, the FAA will:
- Issue a TSO authorization to the applicant, and
- Include any TSO deviations that were granted during the approval process.
A TSO deviation is FAA permission to depart from a specific TSO performance standard when the applicant shows an equivalent level of safety.
Why it matters operationally: As a pilot, the TSO marking on a piece of equipment is your assurance that the manufacturer was authorized by the FAA to produce that article to a known minimum performance standard — including any approved deviations from the baseline TSO.