The FAA may amend a type certificate when the holder of the type certificate receives FAA approval to modify an aircraft design from its original design. An amended type certificate approves not only the modification, but also how that modification affects the original design.
For information regarding the amended type certificate process, you may contact your certificate management office or the FAA Aircraft Certification Office. We recommend that you follow the Original Design Approval Process. You may also find it helpful to review related order, Order 8110.4, Type Certification.