A disclosed connector assembly for a refrigerant system mounted within an aircraft includes a metal seal disposed within a seal bore of a connector and compressed against a seal face of a nipple secured to the connector by a threaded member. The connector includes a seal bore that receives the metal seal with the inner portion of the seal bore open to the bore. In one example, the connector and nut are formed from aluminum and the nipple is formed from stainless steel and includes an aluminum coating applied to surfaces in contact with the metal seal and the connector.