Annual Inspection – An Annual Inspection is complete inspection of an aircraft and engine, required by the Code of Federal Regulations, to be accomplished every 12 calendar months on all certificated aircraft. Only an A&P technician holding an Inspection Authorization (IA) can conduct an annual inspection.
From Aviation Glossary (Scott) – I need to clarify this definition from the FAA. Like many Aviation terms the definition depends on the context in which the term is used. In this case I pulled the definition from FAA-H-8083-25A Pilot’s Handbook. The statement “accomplished every 12 calendar months on all certificated aircraft” is not completely accurate. Aircraft operated under 14 CFR 121 or 14 CFR 135 are maintained and inspected under a “Continuous Airworthiness Maintenance Program” approved by the Administrator (FAA). Also, part 91 aircraft may be maintained by an approved program if so authorized and will not need an “Annual Inspection”.