14 CFR § 21.97

An applicant for approval of a major change in type design must—

Provide substantiating data and necessary descriptive data for inclusion in the type design;

Show that the change and areas affected by the change comply with the applicable requirements of this subchapter, and provide the FAA the means by which such compliance has been shown; and

Provide a statement certifying that the applicant has complied with the applicable requirements.

Approval of a major change in the type design of an aircraft engine is limited to the specific engine configuration upon which the change is made unless the applicant identifies in the necessary descriptive data for inclusion in the type design the other configurations of the same engine type for which approval is requested and shows that the change is compatible with the other configurations.