5 C.F.R. § 2419.6
(d) Appeal to the authority head. Parties may not appeal interlocutory rulings by the presiding officer to the authority head.
(1) Except in case of default, if the defendant is determined in the decision to be liable for a civil penalty or assessment, the defendant may appeal such decision to the authority head by filing a notice of appeal with the authority head in accordance with this section. A notice of appeal shall be accompanied by a written brief specifying exceptions to the decision and reasons supporting the exceptions.