FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) During an investigation conducted under this subpart, a party may submit to the Presiding Officer --

(1) A list of witnesses to be called, specifying the subject matter of the expected testimony of each witness, and

(2) A list of exhibits to be considered for inclusion in the record.

(b) If the Presiding Officer determines that the testimony of a witness or the receipt of an exhibit in accordance with paragraph (a) of this section will be relevant, competent and material to the investigation, the Presiding Officer may subpoena the witness or use the exhibit during the investigation.