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The purpose of this document is threefold: (1) to review the problem of moisture in avionics equipment, (2) to outline methods for correcting conditions of excess moisture in existing avionics installations, and (3) to recommend design practices for new avionics cooling system installations which will minimize the adverse effects of moisture.

This Aerospace Recommended Practice (ARP) outlines the causes and impacts of moisture and/or condensation in avionics equipment and provides recommendations for corrective and preventative action.

These recommendations are written to cover the testing of air conditioning equipment as installed in the prototype aircraft for the purpose of: A Demonstrating safety of the installation. B Demonstrating performance of the installation. a Aircraft ducting and distribution system. b Component parts (i.e., vendors equipment) C Obtaining data for future design.

This recommended practice covers automatic cabin temperature control systems of the following types for pressurized and unpressurized cabins: Type I - Proportioning. Type II - On-Off, or Cycling. Type III - Floating, including modifications thereof.

These recommendations are written to cover automatic cabin temperature controls under three classifications, namely:

The purpose of this report is to provide information on ozone and its control in high altitude aircraft environmental systems. Sources of this information are listed in the selected bibliography appearing at the end of this report, to which references are made throughout.

Heat transfer is the transport of thermal energy from one point to another. Heat is transferred only under the influence of a temperature gradient or temperature difference. The direction of heat transfer is always from the point at the higher temperature to the point at the lower temperature, in accordance with the second law of thermodynamics. The fundamental modes of heat transfer are conduction, convection, and radiation. Conduction is the net transfer of energy within a fluid or solid occurring by the collisions of molecules, atoms, or electrons. Convection is the transfer of energy resulting from fluid motion. Convection involves the processes of conduction, fluid motion, and mass transfer. Radiation is the transfer of energy from one point to another in the absence of a transporting medium. In practical applications several modes of heat transfer occur simultaneously.

Heat transfer is the transport of thermal energy from one point to another. Heat is transferred only under the influence of a temperature gradient or temperature difference. The direction of heat transfer is always from the point at the higher temperature to the point at the lower temperature, in accordance with the second law of thermodynamics. The fundamental modes of heat transfer are conduction, convection, and radiation. Conduction is the net transfer of energy within a fluid or solid occurring by the collisions of molecules, atoms, or electrons. Convection is the transfer of energy resulting from fluid motion. Convection involves the processes of conduction, fluid motion, and mass transfer. Radiation is the transfer of energy from one point to another in the absence of a transporting medium. In practical applications several modes of heat transfer occur simultaneously.

This specification is written to cover heating and ventilating equipment under four main classifications, namely; A HEATING AND VENTILATING EQUIPMENT - GENERAL - Dealing with features applicable to all makes and uses. B HEATING AND VENTILATING EQUIPMENT - MILITARY - Dealing with features applicable only to military aircraft. C HEATING AND VENTILATING EQUIPMENT - COMMERCIAL - Dealing with features applicable only to commercial aircraft. D DESIRABLE DESIGN FEATURES - General information for use of those concerned in meeting requirements contained herein.

This specification is written to cover heating and ventilating equipment under four main classifications, namely; A HEATING AND VENTILATING EQUIPMENT - GENERAL - Dealing with features applicable to all makes and uses. B HEATING AND VENTILATING EQUIPMENT - MILITARY - Dealing with features applicable only to military aircraft. C HEATING AND VENTILATING EQUIPMENT - COMMERCIAL - Dealing with features applicable only to commercial aircraft. D DESIRABLE DESIGN FEATURES - General information for use of those concerned in meeting requirements contained herein.

This Aerospace Recommended Practice (ARP) defines tests to be performed on hydraulically, electrically, pneumatically, and mechanically actuated air valves. They may be further defined as those valves that function in response to externally applied forces or in response to variations in upstream and/or downstream duct air conditions in order to maintain a calibrated duct air condition (e.g., air flow, air pressure, air temperature, air pressure ratio, or air shutoff).

This Aerospace Recommended Practice (ARP) defines tests to be performed on hydraulically, electrically, pneumatically, and mechanically actuated air valves. They may be further defined as those valves that function in response to externally applied forces or in response to variations in upstream and/or downstream duct air conditions in order to maintain a calibrated duct air condition (e.g., air flow, air pressure, air temperature, air pressure ratio, or air shutoff).

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 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 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 document supplements and in some cases supersedes the recommendations presented in ARP 85D, which refers to subsonic civil transports.

This publication outlines general design concepts considered the minimum acceptable standards for use in electrical and electronic equipment. The objective is increased reliability of the equipment without penalizing the aircraft performance.

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.