Cabin Environment Control System

Aircraft are flown at high altitudes for two reasons. First, an aircraft flown at high altitude consumes less fuel for a given airspeed than it does for the same speed at a lower altitude because the aircraft is more efficient at a high altitude. Second, bad weather and turbulence may be avoided by flying in … Read more

Composition of the Atmosphere The mixture of gases that make up the earth’s atmosphere is commonly called air. It is composed principally of 78 percent nitrogen and 21 percent oxygen. The remaining 1 percent is made up of various gases in smaller quantities. Some of these are important to human life, such as carbon dioxide, … Read more

The negative effects of reduced atmospheric pressure at flight altitudes, forcing less oxygen into the blood, can be overcome. There are two ways this is commonly done: increase the pressure of the oxygen or increase the quantity of oxygen in the air mixture. Large transport-category and high-performance passenger aircraft pressurize the air in the cabin. … Read more

Aircraft oxygen systems provide supplemental oxygen to the flight crew and passengers when cabin altitude becomes too high for normal breathing. Depending on the aircraft and its operating altitude, these systems may use gaseous oxygen stored in cylinders or chemical oxygen generators. Oxygen systems vary from simple portable units used in light aircraft to complex … Read more

Oxygen System Servicing Servicing Gaseous Oxygen Gaseous oxygen systems are prevalent in general, corporate, and airline aviation. The use of lightweight aluminum and composite storage cylinders has improved these simple and reliable life support systems. All gaseous oxygen systems require servicing and maintenance. Various procedures and requirements to perform these functions are covered in this … Read more

Pressure of the Atmosphere The gases of the atmosphere (air), although invisible, have weight. A one-square-inch column of air stretching from sea level into space weighs 14.7 pounds. Therefore, it can be stated that the pressure of the atmosphere, or atmospheric pressure, at sea level is 14.7 psi. [Figure 1] Atmospheric pressure is also known … Read more

Aircraft cabin pressurization systems require a source of compressed air to maintain a safe and comfortable cabin altitude at high flight levels. The method used depends largely on the type of engine installed. Reciprocating-engine aircraft may use superchargers, turbochargers, or dedicated compressors, while turbine-powered aircraft normally use bleed air from the engine compressor section. The … Read more

Aircraft cabin pressure control systems regulate the pressure inside the fuselage so that passengers and crew can remain comfortable and receive adequate oxygen at high altitudes. To do this, the system controls cabin altitude, rate of cabin pressure change, and the pressure difference between the inside and outside of the aircraft. Modern pressurization systems use … Read more

Aircraft air conditioning systems are designed to maintain a comfortable and safe cabin environment by controlling temperature, airflow, and humidity during flight and on the ground. Modern aircraft use either air cycle systems, which are common on turbine-powered aircraft, or vapor cycle systems, which are typically found on reciprocating-engine aircraft. Understanding how these systems cool … Read more