Pack (aircraft)
Encyclopedia
PACK, Pneumatic Air Cycle Kit. The Kit usually consists of an Air cycle machine
(ACM), a set of heat exchangers, water separators and temperature and pressure control valves and sensors. Additional components may be included depending on the design.
The main function of the PACK is to provide cabin air pressurization and temperature conditioning. To operate, a PACK requires a source of high pressure and temperature air, usually obtained from a bleed of the compressor of a gas turbine engine such as a turbofan, turbojet or turbo-shaft. When heating is needed, the bleed air bypasses the ACM and is routed directly into the compartment to be heated. When cooling is needed, usually during ground operations, the ACM lowers the temperature of the bleed air before introducing it in the cabin. During the cooling process, water vapor condenses, creating the need for water separators.
Many aircraft pilots, operators and some manufacturers have no knowledge of the acronym origin and incorrectly use "pack" as a word, or sometimes as an abbreviation for the word "package".
Air cycle machine
An air cycle machine is the refrigeration unit of the environmental control system used in pressurized gas turbine-powered aircraft. Normally an aircraft has two or three of these ACM. Each ACM and its components are often referred as an Air Conditioning Pack.The air cycle cooling process uses...
(ACM), a set of heat exchangers, water separators and temperature and pressure control valves and sensors. Additional components may be included depending on the design.
The main function of the PACK is to provide cabin air pressurization and temperature conditioning. To operate, a PACK requires a source of high pressure and temperature air, usually obtained from a bleed of the compressor of a gas turbine engine such as a turbofan, turbojet or turbo-shaft. When heating is needed, the bleed air bypasses the ACM and is routed directly into the compartment to be heated. When cooling is needed, usually during ground operations, the ACM lowers the temperature of the bleed air before introducing it in the cabin. During the cooling process, water vapor condenses, creating the need for water separators.
Many aircraft pilots, operators and some manufacturers have no knowledge of the acronym origin and incorrectly use "pack" as a word, or sometimes as an abbreviation for the word "package".