A progressive inspection program allows an aircraft to be inspected in segments over shorter time periods rather than taking it out of service for the full annual inspection. The inspection items are divided into phases to be completed within a 200-hour cycle, allowing the aircraft to remain airworthy and fly daily. Large or turbine aircraft require continuous inspection programs approved by the FAA that involve different levels of checks with increasing detail, from A-checks to more comprehensive D-checks. Special inspections are also required on certain items like altimeters, transponders, and ELTs at prescribed intervals.