How are fluid lines in aircraft commonly identified?

Fluid lines in aircraft are commonly identified through the use of markers and geometric symbols. This system provides a clear and standardized way to communicate vital information about the fluid lines, such as their function, direction of fluid flow, and the type of fluid they carry.

Markers can include colors or codes that represent specific fluids, while geometric symbols can indicate the kind of fittings or connectors required at various points along the line. This form of identification is crucial for maintaining the safety and efficiency of fluid systems in aircraft, ensuring that maintenance personnel can quickly and accurately identify components during inspections or repairs.

In contrast, options such as weight and size indicators, length and flexibility codes, and material and density specifications do not effectively communicate the necessary operational information about these fluid lines, reducing their practicality and utility in aircraft maintenance and operation.