Section 16.5 - Separation of functions(a) Proceedings under this part, including hearings under subpart F of this part, will be prosecuted by an agency attorney.(b) After issuance of an initial determination in which the FAA provides the opportunity for a hearing, an agency employee engaged in the performance of investigative or prosecutorial functions in a proceeding under this part will not, in that case or a factually related case, participate or give advice in an initial decision by the hearing officer, or a final decision by the Associate Administrator or designee on written appeal, and will not, except as counsel or as witness in the public proceedings, engage in any substantive communication regarding that case or a related case with the hearing officer, the Associate Administrator on written appeal, or agency employees advising those officials in that capacity.(c) The Chief Counsel, the Assistant Chief Counsel for Litigation, or an attorney on the staff of the Assistant Chief Counsel for Litigation advises the Associate Administrator regarding an initial decision, an appeal, or a final decision regarding any case brought under this part.