Whenever a person holding an agricultural aircraft operator certificate ceases operations under this part, he shall surrender that certificate to the FAA Flight Standards District Office last having jurisdiction over his operation. [Doc. No. 1464, 30 FR 8106, June 24, 1965, as amended by Amdt. 137-13, 54 FR 39294, Sept. 25, 1989; 54 FR 52872, Dec. 22, 1989]