Where is low-pressure Liquid Oxygen (LOX) usually found?

Low-pressure Liquid Oxygen (LOX) is primarily found in single and dual-seat aircraft, particularly those that require supplemental oxygen systems for high-altitude flight operations. In these aircraft, LOX is used to provide breathable oxygen to the pilot in conditions where the ambient air pressure is too low for safe breathing, such as at high altitudes.

The use of LOX in single and dual-seat aircraft is due to their design requirements for operations in higher altitude environments and the significant advantages LOX offers in terms of weight and storage efficiency compared to other forms of oxygen. It allows for a more compact system that supports extended operational capabilities, including fighter jets and high-performance trainers.

In contrast, large commercial airliners typically use onboard pressurization systems that maintain cabin pressure at levels sufficient for passenger breathing, which negates the need for onboard LOX. Cargo planes might have oxygen systems but are not primarily associated with LOX, as their operations may not demand the same high-altitude performance requirements. Helicopters, while they do operate at altitude, generally rely on lower altitude operations, and their oxygen needs can often be met through different systems tailored to their specific operational profiles.