(a) When a complaint or request for determination stands submitted to the Secretary for final decision on the merits, he or she may dispose of the issues presented by entering an appropriate order, which will include a statement of the reasons for his or her findings and conclusions. Such an order shall be deemed a final order of the Secretary.

(b) The final order of the Secretary shall include, where necessary, directions regarding an appropriate refund or credit of the fee increase or newly established fee which is the subject of the complaint or request for determination.

(c) If the Secretary has not issued a final order within 120 days after the filing of a complaint by an air carrier or foreign air carrier, the decision of the administrative law judge shall be deemed to be the final order of the Secretary.