This specification covers forced-air-cooled, integrated avionics racks, herein after referred to as racks, used for various military avionics systems. The racks are designed to accommodate Standard Electronic Modules (SEMs) using multiple tiers. Intended Use: These racks are required to withstand forward acceleration values of 4g's and sudden temperature changes from −57°C to +95°C (−70°F to +203°F), which exceed the requirements for commercial aircraft. In addition, these racks must mate with modules and primary and secondary backplanes which are unique to military platforms. A sample of an integrated rack configuration is given in figure 8.