Complex

A system is “complex” when its operation, failure modes, or failure effects are difficult to comprehend without the aid of analytical methods or structured assessment methods. FMEA and FTA are examples of such structured assessment methods. Increased system complexity is often caused by such items as sophisticated components and multiple interrelationships. For these types of systems, portion of the compliance may be shown by the use of DALs such as by processes in RTCA/DO-178B or RTCA/DO-254 or equivalent. See the definitions for “conventional” and “simple” for more information.