14 CFR 47.43 - Invalid registration.
(a) The registration of an aircraft is invalid if, at the time it is made -
(1) The aircraft is registered in a foreign country;
(2) The applicant is not the owner;
(3) The applicant is not qualified to submit an application under this part; or
(4) The interest of the applicant in the aircraft was created by a transaction that was not entered into in good faith, but rather was made to avoid (with or without the owner's knowledge) compliance with 49 U.S.C. 44101- 44104 44101-44104.
(b) If the registration of an aircraft is invalid under paragraph (a) of this section, the holder of the invalid Certificate of Aircraft Registration, AC Form 8050-3, must return it as soon as possible to the Registry.