41 C.F.R. § 102-33.145 – Automated system for accounting aircraft costs.

(a) If you own Federal aircraft or operate bailed aircraft, you must use an automated system to track aircraft costs by collecting FAIRS-required data.
(b) Agencies using only CAS aircraft and no Federal aircraft must keep records sufficient for FAIRS reporting, but are not required to have an automated system. See §§ 102-33.260 and 102-33.265 for CAS reporting requirements.