MSG-3 (Maintenance Steering Group) "Operator/Manufacturer Scheduled Maintenance Development" is a document developed by the Airlines For America (A4A) (formerly the Air Transport Association or ATA). It aims to present a methodology for developing scheduled maintenance tasks and intervals, which will be acceptable to the regulatory authorities, the operators, and the manufacturers. The main idea behind this concept is to recognise the inherent reliability of aircraft systems and components, avoid unnecessary maintenance tasks, and achieve increased efficiency. The underlying principles are that: