A, B, C, And D Checks

In the aviation industry, A, B, C, and D checks refer to the periodic maintenance checks that an aircraft must go through to ensure its optimal performance and safety. 'A' checks occur approximately every 500-800 flight hours, or every 200-300 flights, and involve a detailed inspection of the aircraft's interior and exterior, including the landing gear, flight controls, and emergency equipment. 'B' checks are more comprehensive and occur approximately every four to six months. They involve a more in-depth inspection of the aircraft's systems and components. 'C' checks are even more comprehensive and occur approximately every 20-24 months. They involve a detailed inspection of the aircraft's structure, systems, and components, and often require the aircraft to be taken out of service for a period of time. 'D' checks are the most comprehensive and occur approximately every six to ten years. They involve a complete overhaul of the aircraft, including the inspection and repair of the aircraft's structure and systems, and often require the aircraft to be taken out of service for a period of time.