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This document considers the cooling of equipment installed in equipment centers, which usually consist of rack-mounted equipment and panel mounted equipment in the flight deck. Instances where these two locations result in different requirements are identified. This document generally refers to the cooled equipment as E/E equipment, denoting that both electrical and electronic equipment is considered, or as an E/E equipment line-replaceable-unit (LRU). The majority of cooled equipment takes the form of LRUs. The primary focus of this document is E/E equipment which uses forced air cooling to keep the equipment within acceptable environmental limits. These limits ensure the equipment operates reliably and within acceptable tolerances. Cooling may be supplied internally or externally to the E/E equipment case. Some E/E equipment is cooled solely by natural convection, conduction, and radiation to the surrounding environment.

This SAE Aerospace Information Report (AIR) covers the design parameters for various methods of humidification applicable to aircraft, the physiological aspects of low humidities, the possible benefits of controlling cabin humidity, the penalties associated with humidification, and the problems which must be solved for practical aircraft humidification systems. The design information is applicable to commercial and military aircraft. The physiological aspects cover all aircraft environmental control applications.

This SAE Aerospace Information Report (AIR) outlines concepts for the design and use of fault isolation equipment that have general application. The specific focus is on fault isolation of environmental control systems (ECS) in commercial transports. Presented are general fault isolation purposes, design principles, and demonstration of compliance criteria. These are followed by three design examples to aid in understanding the design principles. Future trends in built-in-test-equipment (BITE) design are discussed, some of which represent concepts already being implemented on new equipment.

The intent of this report is to encourage that the thermal management system architecture be designed from a global platform perspective. Separate procurements for air vehicle, propulsion system, and avionics have contributed to the development of aircraft that are sub-optimized from a thermal management viewpoint. In order to maximize the capabilities of the aircraft for mission performance and desired growth capability, overall system efficiency and effectiveness should be considered. This document provides general information about aircraft Thermal Management System Engineering (TMSE). The document also discusses approaches to processes and methodologies for validation and verification of thermal management system engineering. Thermal integration between the air vehicle, propulsion system, and avionics can be particularly important from a thermal management standpoint.

This SAE Aerospace Recommended Practice (ARP) provides symbols to schematically represent aerospace vehicle environmental system components on functional flow schematic drawings and graphical computerized output. The symbols are for use on simplified diagrams that provide basic information about an environmental system. Symbols are provided to represent basic types of components used in environmental systems. Simple variations of basic symbol types are provided. Words on the schematic diagram, special symbol codes, or symbols that combine basic symbol types (Section 5) can be used to augment the basic symbols when appropriate. Special or combined symbols not contained in this document should be defined on the schematic diagram. An example of a complete schematic is given in Section 6. A bibliography of other documents on environmental system symbols is found in Appendix A.

This SAE Aerospace Recommended Practice (ARP) discusses design philosophy, system and equipment requirements, environmental conditions, and design considerations for rotorcraft environmental control systems (ECS). The rotorcraft ECS comprises that arrangement of equipment, controls, and indicators which supply and distribute dehumidified conditioned air for ventilation, cooling and heating of the occupied compartments, and cooling of the avionics. The principal features of the system are: a A controlled fresh air supply b A means for cooling (air or vapor cycle units and heat exchangers) c A means for removing excess moisture from the air supply d A means for heating e A temperature control system f A conditioned air distribution system The ARP is applicable to both civil and military rotorcraft where an ECS is specified; however, certain requirements peculiar to military applications—such as nuclear, biological, and chemical (NBC) protection—are not covered.

This SAE Aerospace Recommended Practice (ARP) discusses design philosophy, system and equipment requirements, installation environment and design considerations for military and commercial aircraft systems within the Air Transport Association (ATA) ATA 100 specification, Chapter 36, Pneumatic. This ATA system/chapter covers equipment used to deliver compressed air from a power source to connecting points for other systems such as air conditioning, pressurization, ice protection, cross-engine starting, air turbine motors, air driven hydraulic pumps, on board oxygen generating systems (OBOGS), on board inert gas generating systems (OBIGGS), and other pneumatic demands. The engine bleed air system includes components for preconditioning the compressed air (temperature, pressure or flow regulation), ducting to distribute high or low pressure air to the using systems, and sensors/instruments to indicate temperature and pressure levels within the system.

This SAE Aerospace Standard (AS) defines the requirements for air cycle air conditioning systems used on military air vehicles for cooling, heating, ventilation, and moisture and contamination control. General recommendations for an air conditioning system, which may include an air cycle system as a cooling source, are included in MIL-E-18927E and JSSG-2009. Air cycle air conditioning systems include those components which condition high temperature and high pressure air for delivery to occupied and equipment compartments and to electrical and electronic equipment. This document is applicable to open and closed loop air cycle systems. Definitions are contained in Section 5 of this document.

This SAE Aerospace Standard (AS) defines the requirements for air cycle air conditioning systems used on military air vehicles for cooling, heating, ventilation, and moisture and contamination control. General recommendations for an air conditioning system, which may include an air cycle system as a cooling source, are included in MIL-E-18927E (AS) and JSSG-2009. Air cycle air conditioning systems include those components which condition high temperature and high pressure air for delivery to occupied and equipment compartments and to electrical and electronic equipment. This document is applicable to open and closed loop air cycle systems. Definitions are contained in Section 5 of this document.

This SAE Aerospace Recommended Practice (ARP) describes a method of conducting an endurance test using contaminated air when the applicable specification requires non-recirculation of the contaminants. The objective of the test is to determine the resistance of the engine mounted components to wear or damage caused by the contaminated air. The method described herein calls for non-recirculation of the contaminants and is intended to provide a uniform distribution of the contaminant at the inlet to the Unit Under Test (UUT). The UUT may require the use of a hydraulic fluid for actuation of components within the test unit. Contamination of the test hydraulic fluid is not part of this recommended practice. If contaminated hydraulic fluid is required by the applicable test specification, refer to MAP749.

This AIR is arranged in the following two sections: 2E - Thermodynamic Characteristics of Working Fluids, which contains thermodynamic diagrams for a number of working fluids currently in use and supplied by various industrial firms. 2F - Properties of Heat Transfer Fluids, which contains data, primarily in graphical form, on fluids that are frequently used in fluid heat transfer loops. Other properties of the environment, gases, liquids, and solids, can be found, as follows, in AIR1168/9: 2A-Properties of the Natural Environment 2B-Properties of Gases 2C-Properties of Liquids 2D-Properties of Solids

This report contains background information on life cycle cost elements and key ECS cost factors. Elements of life cycle costs are defined from initial design phases through operational use. Information on how ECS designs affect overall aircraft cost and information on primary factors affecting ECS costs are discussed. Key steps or efforts for comparing ECS designs on the basis of LCC are outlined. Brief descriptions of two computer programs for estimating LCC of total aircraft programs and their use to estimate ECS LCC, are included.

This SAE Aerospace Recommended Practice (ARP) provides symbols to schematically represent aerospace vehicle environmental system components on functional flow schematic drawings and graphical computerized output. The symbols are for use on simplified diagrams that provide basic information about an environmental system. Symbols are provided to represent basic types of components used in environmental systems. Simple variations of basic symbol types are provided. Words on the schematic diagram, special symbol codes, or symbols that combine basic symbol types (Section 5) can be used to augment the basic symbols when appropriate. Special or combined symbols not contained in this document should be defined on the schematic diagram. An example of a complete schematic is given in Section 6. A bibliography of other documents on environmental system symbols is found in Appendix A.

This ARP covers the basic criteria for the design of cabin pressure control systems (CPCS) for general aviation, commercial and military pressurized aircraft.

This ARP discusses design philosophy, system and equipment requirements, environmental conditions, and design considerations for helicopter environmental control systems (ECS). The helicopter ECS comprises that arrangement of equipment, controls, and indicators which supply and distribute dehumidified conditioned air for ventilation, cooling and heating of the occupied compartments, and cooling of the avionics. The principal features of the system are: a A controlled fresh air supply b A means for cooling (air or vapor cycle units and heat exchangers) c A means for removing excess moisture from the air supply d A means for heating e A temperature control system f A conditioned air distribution system The ARP is applicable to both civil and military helicopters where an ECS is specified; however, certain requirements peculiar to military applications, such as nuclear, biological and chemical (NBC) protection, are not covered.

This Aerospace Information Report (AIR) outlines the design considerations and criteria for the control of water carryover from the environmental control system (ECS) with respect to causes and indicated corrective or preventative action. In addition, condensation on structure will be reviewed with possible preventative action described.

This document summarizes types of heat sinks and considerations in relation to the general requirements of aircraft heat sources, and it provides information to achieve efficient utilization and management of these heat sinks. In this document, a heat sink is defined as a body or substance used for removal of the heat generated by hydrodynamic or thermodynamic processes. This document provides general data about airborne heat sources, heat sinks, and modes of heat transfer. The document also discusses approaches to control the use of heat sinks and techniques for analysis and verification of heat sink management. The heat sinks are for aircraft operating at subsonic and supersonic speeds.

This AIR is arranged in the following two sections: 2E - Thermodynamic Characteristics of Working Fluids, which contains thermodynamic diagrams for a number of working fluids currently in use and supplied by various industrial firms. 2F - Properties of Heat Transfer Fluids, which contains data, primarily in graphical form, on fluids that are frequently used in fluid heat transfer loops. Other properties of the environment, gases, liquids, and solids, can be found, as follows, in AIR1168/9: 2A-Properties of the Natural Environment 2B-Properties of Gases 2C-Properties of Liquids 2D-Properties of Solids

A life support system (LSS) is usually defined as a system that provides elements necessary for maintaining human life and health in the state required for performing a prescribed mission. The LSS, depending upon specific design requirements, will provide pressure, temperature, and composition of local atmosphere, food, and water. It may or may not collect, dispose, or reprocess wastes such as carbon dioxide, water vapor, urine, and feces. It can be seen from the preceding definition that LSS requirements may differ widely, depending on the mission specified, such as operation in Earth orbit or lunar mission. In all cases the time of operation is an important design factor. An LSS is sometimes briefly defined as a system providing atmospheric control and water, waste, and thermal management.

This SAE Aerospace Information Report (AIR) outlines concepts for the design and use of fault isolation equipment that have general application. The specific focus is on fault isolation of environmental control systems (ECS) in commercial transports. Presented are general fault isolation purposes, design principles, and demonstration of compliance criteria. These are followed by three design examples to aid in understanding the design principles. Future trends in built-in-test-equipment (BITE) design are discussed, some of which represent concepts already being implemented on new equipment.