The following item is from the New York Times 24 Aug 96...

COMPUTER INTERFACE CONTRIBUTES TO PLANE CRASH
The crash of a Cali-bound American Airlines jet last December in Colombia,
S.A., occurred because the plane's captain entered an incomplete command
into the onboard computer -- and the default action taken by the software
pointed the plane in the wrong direction. The beacons at the Cali and
Bogota airports both begin with the letter R, which is the only character
the pilot typed; instead of proceeding toward Cali, the plane turned in 
the opposite direction (toward Bogata) and crashed into a mountain.