14 C.F.R. § 13.127

The presiding officer must issue a written report based on the record developed during the formal investigation, including a summary of principal conclusions. A summary of principal conclusions must be prepared by the official who issued the order of investigation in every case that results in no action, or no action as to a particular party to the investigation. All such reports must be furnished to the parties to the investigation and made available to the public on request.