14 C.F.R. § 240.2
Upon the demand of a special agent or auditor of the Department, and upon the presentation of the identification card and credentials issued to him or her in accordance with this part: Any air carrier or foreign air carrier shall forthwith permit such special agent or auditor to inspect and examine all lands, buildings and equipment; any air carrier, foreign air carrier or ticket agent shall forthwith permit such special agent or auditor to inspect and examine all accounts, records, memorandums, documents, papers and correspondence now or hereafter existing, and kept or required to be kept by the air carrier, foreign air carrier, or ticket agent, and shall permit such special agent or auditor to make such notes and copies thereof as he or she deems appropriate.
14 C.F.R. §240.2
Sec. 204(a), Federal Aviation Act of 1958, as amended, 72 Stat. 743; (49 U.S.C. 1324 )