Aircraft components, Breathing apparatus, Oxygen, Oxygen masks, Air transport engineering, Design, Installation, Gas circuits, Service pressure, Working range, Air safety, Safety measures, Equipment safety, Compatibility, Chemical-resistant materials, Pipe couplings, Pipe connections, Pipework systems, Filters, Pressure regulators, Valves, Joints, Pressure control, Maintenance, Climatic hazards, Ice, Moisture, Control switches, Control knobs, Strength of materials, Mechanical properties of materials, Welded joints, Soldered joints, Brazed joints, Cleaning, Identification methods, Marking