What does the dash number following the AN number indicate?

The dash number following the AN number serves to specify the size of the tubing or hose. In the Army-Navy (AN) aviation specification system, the AN number is a standard identification code that is used to denote a particular type of fitting or tubing. The dash number provides a critical dimension in terms of the internal diameter of the tube or hose, which is essential for maintaining proper flow characteristics in fluid lines.

This sizing system is integral to understanding how different components will fit together and function within a hydraulic or pneumatic system. Correct sizing ensures compatibility with other components and helps prevent issues such as leaks or pressure loss, which can occur if components are mismatched.

Understanding this aspect is vital for anyone working in fields involving fluid systems, as it allows for accuracy in selecting parts that ensure the overall integrity and performance of the system.