14 CFR §65.104

1. (a)To be eligible for a repairman certificate (experimental aircraft builder), an individual must—
   1. (1)Be at least 18 years of age;
   2. (2)Be the primary builder of the aircraft to which the privileges of the certificate are applicable;
   3. (3)Show to the satisfaction of the Administrator that the individual has the requisite skill to determine whether the aircraft is in a condition for safe operations; and
   4. (4)Be a citizen of the United States or an individual citizen of a foreign country who has lawfully been admitted for permanent residence in the United States.
2. (b)The holder of a repairman certificate (experimental aircraft builder) may perform condition inspections on the aircraft constructed by the holder in accordance with the operating limitations of that aircraft.
3. (c)Section 65.103 does not apply to the holder of a repairman certificate (experimental aircraft builder) while performing under that certificate.