14 CFR 47.49: Replacement of Certificate.

(a) If the original Certificate of Aircraft Registration is lost, stolen, or mutilated, the registered owner may submit to the Registry a written request that states the reason a replacement certificate is needed and the fee required by § 47.17. The Registry will send a replacement certificate to the registered owner by email or other electronic or digital means, or, if such means are unavailable, to the registered owner's mailing address or to another mailing address if requested in writing by the registered owner.

(b) The registered owner may request a temporary Certificate of Aircraft Registration pending receipt of a replacement certificate. The Registry issues a temporary Certificate of Aircraft Registration that must be carried in the aircraft until receipt of the replacement certificate.