Failure analysis is a complicated activity, demanding systematic and careful probing into every minor detail to identify the root cause of failure. Investigation into failure of major systems, such as an aircraft accident, requires multidisciplinary knowledge and thus can best be handled by a multidisciplinary expert team. The team should consist of a designer to reconstruct the failure scene by analysis of stress pattern, service loads, environmental influences, etc.; a manufacturer to analyze the probability of the incidence of manufacturing defects and lapses in quality control; a field service engineer to investigate operational and maintenance abuses; and a materials engineer to identify failure mode and material abnormalities. While investigating the failures of major systems, it is important first to correctly identify the subsystem that is responsible for the failure event based on careful cause and effect analysis. Further investigation focuses on that particular subsystem to identify the root cause of failure.