§ 303. Presiding officers. Except as otherwise provided by statute, the agency, one or more members of the agency, or one or more hearing officers designated and empowered by the agency to conduct hearings shall be presiding officers. Hearings shall be conducted in an impartial manner. Upon the filing in good faith by a party of a timely and sufficient affidavit of personal bias or disqualification of a presiding officer, the agency shall determine the matter as part of the record in the case, and its determination shall be a matter subject to judicial review at the conclusion of the adjudicatory proceeding. Whenever a presiding officer is disqualified or it becomes impractical for him to continue the hearing, another presiding officer may be assigned to continue with the case unless it is shown that substantial prejudice to the party will result therefrom.