Section 21.319 - Design changes(a)Classification of design changes.(1) A "minor change" to the design of an article produced under a PMA is one that has no appreciable effect on the approval basis.(2) A "major change" to the design of an article produced under a PMA is any change that is not minor.(b)Approval of design changes.(1) Minor changes to the basic design of a PMA may be approved using a method acceptable to the FAA.(2) The PMA holder must obtain FAA approval of any major change before including it in the design of an article produced under a PMA.