(a) The Hearing Officer to whom a case is assigned may, upon application by any party to the proceeding, issue subpoenas requiring the attendance of witnesses or the production of documentary or tangible evidence at a hearing or for the purpose of taking depositions. However, the application for producing evidence must show its general relevance and reasonable scope. This paragraph does not apply to the attendance of FAA employees or to the production of documentary evidence in the custody of such an employee at a hearing.

(b) A person who applies for the production of a document in the custody of an FAA employee must follow the procedure in §13.49(f). A person who applies for the attendance of an FAA employee must send the application, in writing, to the Hearing Officer setting forth the need for that employee's attendance.

(c) A witness in a proceeding under this subpart is entitled to the same fees and mileage as is paid to a witness in a court of the United States under comparable circumstances. The party at whose instance the witness is subpoenaed or appears shall pay the witness fees.

(d) Notwithstanding the provisions of paragraph (c) of this section, the FAA pays the witness fees and mileage if the Hearing Officer who issued the subpoena determines, on the basis of a written request and good cause shown, that --

(1) The presence of the witness will materially advance the proceeding; and