Which statement is correct regarding Military Standard (MS) flareless fittings?

• A. They require lubrication during installation
• B. They are tightened by applying a specified torque to the nut
• C. They are normally tightened by turning the nut a specified amount
• D. They can only be used with specific tubing types

Answer: (C)

The correct statement about Military Standard (MS) flareless fittings is that they are typically tightened by turning the nut a specified amount. This method of installation is designed to ensure a reliable connection that maintains integrity under high pressure and fluctuating thermal conditions. The specified amount of turns ensures that the fitting is securely fastened without the risk of overtightening, which could damage the fitting or the tubing.

Flareless fittings are designed for ease of installation and maintenance, allowing for a consistent and effective seal. This characteristic also contributes to their widespread use in military and aerospace applications, where reliability is paramount.

While it is true that other types of fittings might require additional considerations, such as lubrication during installation or specific torque specifications, flareless fittings focus on the straightforward method of tightening the nut to a designated rotation, making installation simpler and more reliable in practical applications.