'Fear Factor' 911 Call -- 'He Fell a Couple Stories'

A 911 operator did a double take when he heard a "Fear Factor" stuntman fell "a couple stories" ... leaving the man with two broken ankles.

TMZ obtained the 911 call made by someone on the "Fear Factor" production team immediately after the accident ... which TMZ first reported last month.

During the call, you can hear the operator's shock when the FF staffer tells him how far the stuntman fell -- which, by the way, was an undersell.

The guy actually fell SIX stories ... when his safety harness didn't function properly.