Aviation Regulations Logo
§ 21.120
Responsibility of supplemental type certificate holders to provide written permission for alterations.
A supplemental type certificate holder who allows a person to use the supplemental type certificate to alter an aircraft, aircraft engine, or propeller must provide that person with written permission acceptable to the FAA.
[Doc. No. FAA-2003-14825, 71 FR 52258, Sept. 1, 2006]