c. Special Registration Numbers.
(1) Aircraft owners must apply for a special registration number in writing to AFS-750 and describe the aircraft. Permission to place the special number on the aircraft will be given on Aeronautical Center Form 8050-64, Assignment of Special Registration Numbers. The owner must complete, sign, and return the original form to AFS-750 within 5 days after the special registration number is affixed to the aircraft. The duplicate of Aeronautical Center Form 8050-64 and the present airworthiness certificate must be presented to the FAA representative, who will issue a replacement airworthiness certificate showing the new registration number. The old Certificate of Aircraft Registration and the duplicate Aeronautical Center Form 8050-64 must be carried in the aircraft until the new Certificate of Aircraft Registration is received (see 14 CFR § 47.15(f) and figure 2-1 of this order).