There are specifications, standards and handbooks that prescribe design characteristics of various discrete components that are to be used in new avionic equipment. Also, there are laboratory tests designed to demonstrate the capability of the assembled equipment to meet specific requirements relative to shock, vibration, salt spray, humidity, temperature, pressure, EMI and other characteristics that can be tested and measured in the laboratory. These specifications and laboratory tests currently do not provide a complete description, or accurate simulation, of the real environment. In a Navy test program performed on the A-7 aircraft, for example, it was determined that as a general rule the reliability in the laboratory would be about seven times that found in the fleet.2 While it may not be feasible to duplicate fleet conditions in a laboratory, it is possible to minimize equipment corrosion susceptibilities through improved engineering design once the causes are recognized and understood by the design engineer.
