Section 65.15 - Duration of certificates(a) Except for repairman certificates, a certificate or rating issued under this part is effective until it is surrendered, suspended, or revoked.(b) Unless it is sooner surrendered, suspended, or revoked, a repairman certificate is effective until the holder is relieved from the duties for which the holder was employed and certificated.(c) The holder of a certificate issued under this part that is suspended, revoked, or no longer effective shall return it to the Administrator.(d) Except for temporary certificates issued under § 65.13 , the holder of a paper certificate issued under this part may not exercise the privileges of that certificate after March 31, 2013.Doc. No. 22052, 47 FR 35693, Aug. 16, 1982, as amended by Amdt. 65-51, 73 FR 10668 , Feb. 28, 2008