14 CFR §13.75

1. (a)Within 30 days after service upon the alleged violator of a notice of proposed order of compliance, the alleged violator may—
   1. (1)Submit a written reply;
   2. (2)Submit a written request for an informal conference to discuss the matter with an agency attorney; or
   3. (3)Request a hearing in accordance with subpart D of this part.
2. (b)If, after an informal conference is held or a reply is filed, the agency attorney notifies the person named in the notice that some or all of the proposed agency action will not be withdrawn or will not be subject to a consent order of compliance, the alleged violator may, within 10 days after receiving the agency attorney's notification, request a hearing in accordance with subpart D of this part.
3. (c)Failure of the alleged violator to file a reply or request a hearing within the period provided in paragraph (a) or (b) of this section, as applicable—
   1. (1)Constitutes a waiver of the right to a hearing under subpart D of this part and the right to petition for judicial review; and
   2. (2)Authorizes the Administrator to make any appropriate findings of fact and to issue an appropriate order of compliance, without further notice or proceedings.