Welcome The World Famous Blackjacks of Helicopter Sea Combat Squadron TWO ONE (HSC-21) are based at Naval Air Station North Island, San Diego, California. HSC-21 operates the multi-mission MH-60S Seahawk and unmanned MQ-8C Firescout. The primary mission areas of HSC-21 include Airborne Mine Countermeasures (AMCM), Combat Search and Rescue (CSAR), Anti-Surface Warfare (ASUW), and Combat Logistics. More about us