49 CFR § 821.31 - Complaint procedure.
(a) Filing, time of filing and service on respondent. The order of the Administrator from which an appeal has been taken shall serve as the complaint. The Administrator shall (except as provided in § 821.55(a) with respect to emergency proceedings) file the complaint with the Board within 10 days after the date on which he or she was served with the appeal by the respondent, and shall simultaneously serve a copy of the complaint on the respondent. If the Administrator has determined that the respondent lacks qualification to be a certificate holder, the order filed as the complaint, or an accompanying statement, shall identify the pleaded factual allegations on which this determination is based.
(b) Answer to complaint. The respondent shall (except as provided in § 821.55(b) with respect to emergency proceedings) file with the Board an answer to the complaint within 20 days after the date on which the complaint was served by the Administrator, and shall simultaneously serve a copy of the answer on the Administrator. Failure by the respondent to deny the truth of any allegation or allegations in the complaint may be deemed an admission of the truth of the allegation or allegations not answered. The answer shall also identify any affirmative defenses that the respondent intends to raise at the hearing. The answer may be amended to include affirmative defenses in accordance with the provisions of § 821.12(a).