Transfill Adapter, "N"-Style CGA-540 port and 9/16-18 Scott Fitting
TA-916-N, Adapts CGA-540 to the Scott fitting (9/16-18 threads). Commonly known as the Scott 26875, 5020-1Airline or AS1046 fitting. A nut and nipple is on the CGA-540 end to attach directly to cylinders.

The CGA-540 port end of the adapter has "N" (nut and nipple) port with internal threads.  The other end works with Scott 9/16-18 fittings. 

The North American Industry Standard for oxygen fittings are called ‘CGA-540’ (Compressed Gas Assn. fitting No.540). Aircraft with built-in oxygen systems do not usually use the heavy fittings, instead special lighter weight fill fittings have been developed. We have transfiller fittings for easy refilling your built in system from standard CGA-540 oxygen systems. The adapters shown are for the Aircraft fillers. The (N) is for ‘Nipple’ and the (S) is or ‘Socket’ on the CGA-540 end. An industrial cylinder has a socket. Micro particle filters are used and an O-ring is on the 540 nipple for an airtight fit by hand.

TA Transfill Adapters
The industry standard for oxygen fittings is what is called "CGA-540" (Compressed Gas Association, Arlington VA fitting No.540). Aircraft do not usually use these heavy-weight fittings; instead, special lighter-weight fill fittings have been developed. We have transfiller fittings for these so that you can easily refill your built-in system from standard CGA-540 oxygen systems. The adapters shown are for the aircraft fillers.

There are two types of aircraft oxygen filler fittings found in most GA aircraft. The earliest and most common versions are known as the MS22066 & MS22035. They are a 3/8-24 threaded fitting with a small valve-core or poppet valve for a check-valve that opens during transfilling. The other is a larger 9/16-18 thread commonly known as the SCOTT, Airline or AS1219 fitting.

The TA-380-S & -N are for the MS22066 and MS22035 filler ports. The TA-916-S & -N are for the 9/16-18 SCOTT fittings. The -N is for "nipple" and the -S is for "socket" on the CGA-540 ends. This nomenclature is used because the terms "male" and "female" were being constantly confused with CGA fittings. Micro-particle filters are installed on the 540 ends and an O-ring is on the 540 nipple for an air-tight fit by hand.
Transfilling Overview

Inserts and Related Documents:
Assy. Detail for Product P/N TA916-N