49 C.F.R. § 1122.4
The Board may, in its discretion, commence a nonpublic Board-Initiated Investigation of any matter of national or regional significance that is subject to the jurisdiction of the Board under 49 U.S.C. Subtitle IV, Part A, subject to the provisions of § 1122.6 , by issuing an Order of Investigation. Orders of Investigation shall state the basis for the Board-Initiated Investigation and identify all Board staff who are authorized to conduct the investigation as Investigating Officer(s). The Board may add or remove Investigating Officer(s) during the course of a Board-Initiated Investigation. To the extent practicable, an Investigating Officer shall not participate in any decisionmaking functions in any Formal Board Proceeding(s) opened as a result of any Board-Initiated Investigation(s) that he or she conducted.
49 C.F.R. §1122.4