مطابق با ص 59 سند Part-21 (لینک) مدت اعتبار مجوز مراکز مجاز فعالیت در امر طراحی و تولید متناسب با زمان مورد نیاز برای تولید قطه نیز می باشد.:
An application for type-certification of large aeroplanes and large rotorcraft shall be effective for five years and an application for any other type-certificate shall be effective for three years, unless an applicant shows at the time of application that its product requires a longer period of time for design, development, and testing, and the Agency approves a longer period.
