AA Assisted Ascent AAS Alternative Air Source ABC Airway, Breathing, Circulation (casualty assessment) ABJ Adjustable Buoyancy Jacket ABLJ Adjustable Buoyancy Life Jacket ABT Actual Bottom Time ACI Assistant Club Instructor (BSAC) AD Advanced Diver (BSAC) Adventure Diver (PADI) ADT Actual Dive Time AEDU Admiralty Experimental Diving Unit AGE Arterial Gas Embolism AI Assistant Instructor (PADI) Advanced Instructor (BSAC) AIC Advanced Instructor Course (BSAC) AIE Advaced Instructor Exam (BSAC) AISE Association of Independent Scuba Educators [TD class=