39 CFR 966.13: Ex parte communications.

Ex parte communications are not allowed between a party and the Hearing Official or the Official's staff. For these purposes, ex parte communication means an oral or written communication, not on the public record, with one party only with respect to which reasonable prior notice to all parties is not given, but it shall not include requests for status reports or procedural matters. A memorandum of any communication between the Hearing Official and a party will be transmitted to both parties.