Flight 191, an ill-fated number

American Airlines discontinued use of the Flight 191 label shortly after the May 25, 1979, crash at O'Hare. Yet the number has figured in at least four other air disasters.

In 1967, NASA X-15 Test Flight 191 breaks up over California, killing the test pilot.

In 1972, Prinair Flight 191 crashes on landing in Puerto Rico, killing five.

In 1985, Delta Flight 191 crashes on landing in Dallas-Fort Worth, killing 135, blamed on wind shear.

In 2006, Comair Flight 191 crashes while taking off from the wrong runway in Kentucky, killing 49.