(a) If, after a review of the manufacturer's submitted application, or with respect to an existing technology OB/PWC engine manufacturer's summary information submitted pursuant to §91.107(a), information obtained from any inspection, and such other information as the Administrator may require, the Administrator determines that the application or summary information is complete and that the engine family meets the requirements of this part and the Clean Air Act, the Administrator shall issue a certificate of conformity for the engine family.

(b) The Administrator shall give a written explanation when certification is denied. The manufacturer may request a hearing on a denial. (See §91.124 for procedure.)