See FAA Advisory Circular 20-27G, starting on Page 29:
16. Certifying an Amateur-Built Aircraft Built Outside the United States and Purchased By a U.S. Citizen.
a. Many civil aviation authorities recognize FAA regulatory requirements and certification procedures and in some cases have incorporated them into their certification process. However, some countries’ or jurisdictions’ requirements for certification may not meet FAA requirements. If you purchase an aircraft from one of those countries or jurisdictions, you may not be allowed to operate it in the United States under § 21.191(g). Contact your local FAA office to find out the exact steps to take to meet U.S. certification requirements. You should be prepared to send the following:
(1) If available, documentation obtained by the previous owner from the civil aviation authority of the country or jurisdiction of origin verifying the aircraft was originally certificated as an amateur-built experimental aircraft and that it meets the requirements of § 21.191(g). If such documentation is not available, you will be required to show compliance with § 21.191(g) through the same process used by other applicants (see paragraph 6).
(2) FAA Form 8130-6.
(3) A record of a condition inspection performed on the aircraft by the previous owner, by an inspector authorized by the previous country of registry, or by a U.S. FAA-certificated airframe and powerplant mechanic within a reasonable period of time (about 30 days) before you apply for certification. (Use part 43, Appendix D, Scope and Detail of Items (as Applicable to the Particular Aircraft) to be Included in Annual and 100 Hour Inspections, as a guide for the inspection.) Record the inspection in the aircraft records.
(4) Proper documentation of registration under part 47 (see paragraph 9 for registration procedures).
(5) A letter of request for certification (see Appendix 13 to this AC).
There's also a section on the FAA inspection, and a flow diagram of the entire process.
Ron Wanttaja
