"Typed in" Yeah, sometimes we type LOL!, and especially WTF?GEORGETOWN, S.C. (AP) - 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.
http://www.wjla.com/news/stories/0905/262923.html
I've often worried about getting the two codes mixed up myself. Luckily it's on a sticker on my kneeboard.