In the world of aviation, what's the difference between the codes 7600 and 7500? It turns out plenty of panic.

　　Deputies and a SWAT team surrounded a plane at the Georgetown County Airport after one of the pilots accidentally entered a code saying the aircraft has been hijacked.

　　State Ports Authority Chairman Harry Butler was flying the plane from Georgetown to Columbia on Thursday morning when he lost both radios.

　　The weather wasn't good enough to land in Columbia without the radio, so he turned back to the coast, where it was clear.

　　En route, his co-pilot sent a message on a signal device. He was supposed to type 7600, which means "lost communications." But instead, he punched in 7500, which reports a hijacking, Butler said.

　　Air traffic controllers in Myrtle Beach then notified federal authorities, who sent in the local deputies.

　　Butler said he had no idea what happened until he landed and a dozen deputies surrounded his plane. FBI agents and officials from the Federal Aviation Administration questioned the pair for about two hours, Butler said.