49 C.F.R. § 1554.101
(a) Applicability of this section. This section applies to part 145 certificated repair stations located—
(b) Security Measures. Each repair station described in paragraph (a) of this section must carry out the following measures:
(1) Provide TSA with the name and means of contact on a 24-hour basis of a person or persons designated by the repair station with responsibility for—
(2) When not attended, prevent the unauthorized operation of all large aircraft capable of flight, by using one or more of the means listed in paragraphs (b)(2)(i) through (iv) of this section. In these examples, a key, if used, must only be available to an individual authorized by the repair station who has successfully undergone a check as described in paragraph (b)(3) of this section.
(3) Verify background information of those individuals who are designated as the TSA point(s) of contact and those who have access to any keys or other means used to prevent the operation of large aircraft described in paragraph (b)(2) of this section by one or more of the following means: