The Direct Air Support Center (DASC) is the principal United States Marine Corps aviation command and control system and the air control agency responsible for the direction of air operations directly supporting ground forces. It functions in a decentralized mode of operation, but is directly supervised by the Marine Tactical Air Command Center (TACC) or the Navy Tactical Air Control Center (NTACC). During amphibious or expeditionary operations, the DASC is normally the first Marine Air Command and Control System (MACCS) agency ashore and is usually categorized (i.e. scheduled or on call wave) as the Ground Combat Element's (GCE's) senior Fire Support Coordination Center (FSCC). The DASC's parent unit is the Marine Air Support Squadron (MASS) of the Marine Air Control Group (MACG).