Cabin Environmental Control Systems

Make sure it is your own works with 2 references.

In this discussion activity, address the following in your primary, original posting:

  • Choose one of the cabin environmental control systems and discuss the different types of systems that are used on different aircraft.
  • Next, discuss the differences in each design and why you believe they are designed this way.  

Please reply to at least two of your classmates


The cabin control system I chose to research is the air conditioning/pressurization system. I will examine the air conditioning system on the Airbus A 320/heavy aircraft and F-35/fighters. On modern heavy aircraft, the process begins with the outside air entering through the engine. Once in the engine, it is compressed into the bleed air and transported to A/C packs via pneumatic ducts. Before it reaches the A/C units, the bleed air travels through control valves which regulate the flow of air into the A/C packs. When cold air exits it is mixed with warm air, the bypass valve regulates the amount of hot/cold air mixture. The air is then transferred to the cabin and cockpit. With the air coming in faster than it leaves a high-pressure environment is created. This pressurization system is known as an Isobaric system because the cabin altitude is pre-set.

Next generation Fighters have air conditioning/pressurized environments as well, although the air conditioning portion is similar to that the pilot uses bleed air as A/C  the pressurization is not the same as heavy aircraft. Whereas pressure in heavy planes increases in a linear fashion (as the airplane climbs), fighters us Isobaric Differential which maintains ambient air pressure to a certain altitude. It maintains pressure once a pressure differential is met. Once this is met the cabin/cockpit pressure is increased to maintain the differential. So once the fighter is at high altitudes, the cabin pressure is low enough that oxygen is needed. All the next generation fight are equipped with the On-Board Oxygen Generation System (OBOGS). The OBOGS supplies the pilot with unlimited breathing gas, and reduced infrastructure (LOX system).  Although air conditioning is similar to fighters and heavies, the pressurization is different. Fighter pilots are in a compact area; they fly at very high altitudes and fast speeds. They are required to wear a mask due to the threat of hypoxia, and unconsciousness. Flying at these high altitudes the pilot's blood cannot absorb the oxygen.


One of the cabin environmental control systems is the oxygen system. Humans require continuous oxygen in order to survive; however, oxygen can also be hazardous if handled improperly. The two types of oxygen systems utilized on aircraft are continuous-flow oxygen systems and demand-type oxygen systems.

For continuous-flow oxygen systems, there are continuous-flow regulators and continuous-flow masks. In general, continuous-flow systems allow a metered amount of oxygen to flow constantly. These systems can waste oxygen; however, because of their simplicity, they are often used in small general aviation aircraft (Crane, 2007, p. 674). Often, there are automatic or manual regulators, which are utilized to monitor the air pressure and altitude in order to release the necessary amount of oxygen. Perhaps, the most well-known oxygen equipment is the oxygen masks that are released on aircraft in the event of a sudden loss of cabin pressure.

Demand-type oxygen systems are used in almost all turbine-powered aircraft for the flight crew and a continuous-flow system as a back-up for passengers (Crane, 2007, p. 676). This type of system uses a diluter-demand type regulator or a pressure-demand oxygen regulator. A diluter-demand oxygen system is a popular system that regulates air based on cabin altitude. Additionally, it has an emergency system, which can allow pure oxygen to flow.

There are some precautions that maintainers must take when handling these systems as well. First, petroleum products should not be used on oxygen systems as it can present a fire danger. Although oxygen is not flammable, it can be the source of a combustion incident. Furthermore, maintainers need to be mindful not to allow moisture and contaminates into these systems, as it can cause malfunctions.

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