1. Origin

1.1 Preamble

The first regulations on commercial flight safety were introduced in the USA in the 1930s, at a time when they imposed fixed inspections and time intervals for aircraft components. Towards the end of the 1940s, and in the light of experience feedback, these practices evolved with the introduction of equipment reliability to set the nature of maintenance tasks and their completion intervals. With the advent of new wide-bodied aircraft such as the Boeing 747, preventive maintenance programs were developed in 1968 by the ATA (Air Transport Association) under the name of MSG (747 Maintenance Steering Group). The aim of these programs was to establish an effective scheduled preventive maintenance program before new aircraft entered service, and to modify the initial maintenance...