FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) An Air Carrier Certificate or Operating Certificate issued under this part is effective until --

(1) The certificate holder surrenders it to the Administrator; or

(2) The Administrator suspends, revokes, or otherwise terminates the certificate.

(b) Operations specifications issued under this part, part 121, or part 135 of this chapter are effective unless --

(1) The Administrator suspends, revokes, or otherwise terminates the certificate;

(2) The operations specifications are amended as provided in §119.51;

(3) The certificate holder does not conduct a kind of operation for more than the time specified in §119.63 and fails to follow the procedures of §119.63 upon resuming that kind of operation; or

(4) The Administrator suspends or revokes the operations specifications for a kind of operation.

(c) Within 30 days after a certificate holder terminates operations under part 135 of this chapter, the operating certificate and operations specifications must be surrendered by the certificate holder to the certificate-holding district office.