Both flared and flareless fittings are commonly used in the aerospace industry, depending on the application. The AN (Army-Navy) military standard calls for tighter tolerances and defines all fitting types, where the JIC uses AN specifications as the base line for their own standards and covers fewer sizes.
In the aerospace industry, O-rings are very popular among equipment designers because of their leak-tight connections, typically using a 90 durometer, Buna-N (Nitrile) O-ring. There are two primary types of O-ring boss fittings:
In the aerospace industry, sections of tubing are usually attached with flared or flareless (compression type) fittings, unlike steel pipe. The SAE Aerospace Standard (AS) establishes the requirements for fittings that are used in all types of fluid systems.
The Yellow Jacket Space Program at the Georgia Institute of Technology is a collegiate team that is working to develop liquid rocket engines and sounding rockets for their university run space program.
Manufacturers of fluid system fittings for the Aviation, Space, and Defense industries must meet very stringent requirements.