Aviation oxygen system is a complex mechanism and requires good maintenance. Generally there are three types of aviation oxygen systems that are being used namely, constant flow, altitude adjustable and altitude compensating. All of them can be found in different aircraft types and have plus and minus points.
Constant Flow Systems is the most common and low cost aircraft oxygen system in aviation industry is the constant flow system. It consists of cylinder, regulator and manifold system. All the oxygen systems have cylinders and constitute of steel, composite metals and aluminum. Most of the regulators used are the diaphragm type and the tank pressure is maintained at 2200 psi or pounds per sq. inch. The constant flow systems provide a uniform output pressure at all altitudes.
It is preferred over other types because of the low cost and very low maintenance. The output of the regulator is 2.5 – 3.0 liters/minute at line pressure of 25 to 75 pounds. It’s controlled by the connector attached to the manifold system. Usually factory manufactured oxygen systems in Cessna aircraft use this type of a constant flow system. Portable units of oxygen supply are also based on this system of oxygen supply.
The next oxygen system that are aircraft compatible is ‘altitude adjustable oxygen ‘ system that is like the constant flow system with the additional facility of adjustable control for maintaining the flow. It is done by the control knob for the reading on a gauge that is also calibrated in altitude in symmetry with the aircraft altimeter setting. Though this system is not commonly used in the built in types, portable systems have been incorporating it to a greater deal.
The next system is the ‘Altitude Compensating system’ which has many similar features of altitude adjustable features but in this system the adjustments are done on automatically. Mooney and Beechcraft use this type of aviation oxygen system and few portable devices for oxygen are also manufactured on these lines. The main disadvantage in this system being incorporated in the aircraft is that the oxygen only starts at a certain height of 8000 to 10,000 feet. In case the oxygen system needs to be started at lower altitude, many times is a problem.
Changing needs give rise to new technology and demand leads to modifications. Aircraft oxygen system has been developed, after much trial and error and now have become compatible with different modes of oxygen supply.