Larry Gelbart on killing off "Henry Blake" on "M.A.S.H" - EMMYTVLEGENDS.ORG

One of TV's historical moments,  MASH's most beloved character Colonel Blake was leaving the show, or actually the actor McLean Stevenson was leaving to go on to other projects.  Up until the time, a major character had never been killed or at least, not on this level.  Of course, good bye shows for departing characters were rather commonplace.  In a shocking last scene after Blake's departure, it is announced that his chopper was shot down.  Viewers around the world felt a chill. 

Today, after the barrier was broken, of course, TV character deaths had a little les impact.