MIL-T-8973 (NOTICE 3), MILITARY SPECIFICATION: TUBING, STEEL, CORROSION AND HEAT RESISTANT, FOR AEROSPACE VEHICLE HYDRAULIC SYSTEMS ASSEMBLED BY BRAZING (25 NOV 1998) [S/S BY SAE-AMS5897]., MIL-T-8973 remains inactive for new design; however, the document is valid for acquisitionwhen needed.