Section 302.503 - Contents and service of petition or complaint(a) If a petition or complaint is filed it shall state the reasons why the rates, fares, or charges, or the classification, rule, regulation, or practice complained of are unlawful and shall support such reasons with a full factual analysis.(b) A petition or complaint shall be served by the petitioner or complainant upon the air carrier against whose tariff provision the petition or complaint is filed.(c) Answers to complaints, other than those filed under § 302.506 , shall be filed within seven (7) working days after the complaint is filed.