What does AN, MS and AS stand for? 

AN - Stands for Army / Navy. Used in the early 1940's to standardize military items for WWII. Some AN part#'s are still used today.

MS -  Military standard that for the most part replaced the AN hardware. The MS series was cancelled in 1994 by the secretary of defense. However this caused problems in the aerospace industry because many commercial companies used MS for all or their products. This caused a rush to come up with a new standard to replace the MS standards. There are still some MS part numbers manufactured and used today to support the older aircraft that still requires the MS part#

AS - With the demise of the MS standards a new spec had to be created and that was the AS standards which SAE now governs. Some MS and AN standards were replaced by AS standards and some were changed all together. For example the AN818 nut is now AS5175 and the AN819, MS20819 sleeves are now AS5176.

What Are Aerospace Fittings?

Aerospace Fittings are specifically designed to be used in aerospace and aircraft applications. Aerospace fittings are put through numerous tests to make sure they are of the highest quality for aircraft. Also Aerospace fitting manufacturers must qualify their parts with SAE and be put on a qualified parts list in order for their parts to be used on the aerospace industry.

Common Applications

Aerospace fittings are typically used on aircraft and spacecraft as end fittings, couplings, fasteners and adapters. Part numbers that start with AS, AN or MS are examples of aerospace fittings. These fittings can be what's called flared, flare-less or o-ring boss to accommodate different types of connections on hoses or tube assemblies. 

Benefits Of Aerospace Fittings

By using aerospace fittings you know that the parts you are using are manufactured specifically for an aircraft or aerospace application. They have been extensively tested for safety and strength so you can feel comfortable flying your plane knowing you are using quality certified parts.

How To Buy Aerospace Fittings

When buying aerospace parts pay attention to the part number. Each part of the number has a meaning. You will see AS, AN or MS typically in the beginning of the part number followed by another number that designates the kind of fitting you require. For example AN818-12J is a type of flared nut. Next is a - followed by a number that designates the size. The 12 designates a 3/4" size. Finally is the alloy letter at the end. The material letter designates what material the fitting is made from. J represents 304 stainless steel. If you pay attention to every aspect of the part number you will be fine.

Our Quality Guarantee

Jupiter Stainless & Alloy only sources our aerospace fittings from certified and qualified manufacturers. We guarantee you will receive only high quality aerospace fittings from the best manufacturers in the country and always with a manufacturer certificate of conformance!

Our Shipping Guarantee

Jupiter Stainless & Alloy typically ships within 1-2 days if in stock. If we are out of stock we will notify you of a ship date which should be no more than a few days to a week. All aerospace parts ship with a MFG C of C.

Also be sure to view our Hydraulic Fittings collection page.