MIL-E-18927 Environmental Control Systems, Aircraft, General Requirements ForThis specification establishes the general requirements for design and performance of aircraft Environmental Control Systems (ECS) required for occupied spaces and equipment. It includes pressurization, heating, cooling, ventilating, moisture control, bleed air system, ram air supply, pressure and anti-G suit systems, defogging, defrosting, anti-icing, rain removal, electronic/electrical equipment environment, boundary layer control and related systems.