MRB, MSG-3, MPD, and MRBR

The MSG-3 process is a structured, top-down analysis methodology that evaluates each aircraft system, structure, and powerplant for maintenance-significant items based on the consequences of functional failure. For each item, the MSG-3 logic determines whether a scheduled maintenance task (e.g., lubrication, operational check, inspection, functional check, restoration, discard) is applicable and effective. The MRB comprises representatives from the regulatory authority, the TC holder, and the operators. The MRBR output represents the minimum acceptable maintenance program; individual operators typically augment it based on their operating environment and experience. The MRB process is defined by MRB policy documents issued by the certification authorities.