AMT 221 Aircraft Environmental and Auxiliary Systems

• A decrease in oxygen supply leads to significant changes in body functions, cognition, and consciousness levels, This state, known as 


  hypoxia.
• the second most prevalent substance in the atmosphere, is vital for most living processes.

  Oxygen
• The mixture of gases that make up the earth’s atmosphere is commonly called

  Air
• The crew had neglected to set the pressurization system to automatic during the take-off checks

  Helios Airways Flight 522
• a phenomenon similar to hypoxia, occurs when excessive rapid breathing reduces carbon dioxide levels in the blood.

  Hyperventilation
• is a colorless, odorless gas produced by incomplete combustion of hydrocarbon fuels, such as those used in aviation.

  Carbon monoxide
• are used in flight decks and cabins to provide the crew a warning of the silent danger.

  Carbon monoxide detectors
• consist of chemical tabs mounted on cardboard in the flight deck. When carbon monoxide is detected, the tab changes color through a chemical reaction

  Basic carbon monoxide detectors
• give digital readings of carbon monoxide levels or trigger visual and audible alarms.

  Advanced detectors
• 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.
• is a colorless, odorless gas that liquefies at –183 °C.

  Oxygen
• Oxygen is a colorless, odorless gas that liquefies at –183 °C.
• is tested for water content to prevent freezing in valves and regulators, crucial for aircraft operating in subzero temperatures.

  Aviator’s breathing oxygen
• is a pale blue, transparent liquid. Oxygen can be made liquid by lowering the temperature to below –183 °C or by placing gaseous oxygen under pressure.


  Liquid oxygen (LOX)
• When ignited, it produces oxygenas it burns.

  Sodium chlorate
• are formed chunks of sodium chlorate wrapped inside insulated stainless-steel housings to control the heat produced when activated.

  Solid oxygen candles
• are primarily used as backup oxygen devices on pressurized aircraft.

  Solid oxygen generators
• A decrease in oxygen supply leads to significant changes in body functions, cognition, and consciousness levels.

  hypoxia
• Built-in and portable oxygen systems are used in civilian aviation. They use gaseous or solid oxygen (oxygen generators) as suits the purpose and aircraft.
• Most oxygen storage cylinders are painted

  green, but yellow and other colors may be used as well.
• The most common high-pressure steel oxygen cylinders used in aviation are

  the 3AA and the 3HT.
• The manufactured date and certification number is stamped on each cylinder near the neck.
• in the blood carries oxygen to cells

  Hemoglobin
• is stored and transported in high-pressure cylinders that are typically painted green.

  Pure gaseous oxygen, or nearly pure gaseous oxygen,
• Composite cylinders use

  placards rather than stamping.
• The manufactured date and certification number is

  stamped on each cylinder near the neck
• Oxygen cylinders are considered empty

  when the pressure inside drops below 50 psi.
• Systems are often characterized by the type of regulator used to dispense the oxygen

  continuous-flow and demand flow
• Systems are often characterized by the type of regulator used to dispense the oxygen

  continuous-flow and demand flow
• allows oxygen to exit the storage tank through a valve and passes it through a regulator/reducer attached to the top of the tank.

  continuous-flow oxygen system
• are adjusted by the crew as altitude changes.

  Manual continuous-flow regulators
• s have a built in aneroid

  Automatic continuous-flow regulators
• may consist of a series of plug-in supply sockets fitted to the cabin walls adjacent to the passenger seats to which oxygen masks can be connected.

  passenger section of a continuous-flow oxygen system
• Deployment of the emergency continuous-flow passenger oxygen masks may also be controlled by the

  crew
• s are simple devices made to direct flow to the nose and mouth of the wearer.

  Continuous-flow oxygen masks
• When oxygen is delivered only as the user inhales, or on demand, it is known as

  a demandflow system or a pressure-demand system
• holds back the flow of oxygenuntil the user inhales with a demand-type oxygen mask.


  diluter-demand type regulator
• operate similarly to diluterdemand systems, except that oxygen is delivered through theindividual pressure regulator(s) under higher pressure.

  Pressure-demand oxygen systems
• 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.
• Temperature also changes as altitude is

  increased.