Typically, weapons systems pertaining to ships, land vehicles, guided missiles and aircraft differ in hazards and effects; some are inherent, such as explosives, and some are created due to the specific operating environments (as in, for example, aircraft sustaining flight). In the military aircraft industry safety-critical functions are identified and the overall design architecture of hardware, software and human systems integration are thoroughly analyzed and explicit safety requirements are derived and specified during proven hazard analysis process to establish safeguards to ensure essential functions are not lost or function correctly in a predictable manner. Conducting comprehensive hazard analyses and determining credible faults, failure conditions, contributing influences and causal factors, that can contribute to or cause hazards, are an essentially part of the systems engineering process.