Section 91.1501 - Purpose and definition(a) This subpart requires operators to support the continued airworthiness of each airplane. These requirements may include, but are not limited to, revising the inspection program, incorporating design changes, and incorporating revisions to Instructions for Continued Airworthiness.Amdt. 91-297, 72 FR 63410 , Nov. 8, 2007, as amended by Docket FAA-2018-0119, Amdt. 91-350, 83 FR 9171 , Mar. 5, 2018