According to BBC
, he fell when he was just about 40 meters from the end of his 700 meter walk.
reports that the acrobat took no precautions, using only a six-meter pole to aid his balance. According to The Telegraph
, Aisikaier said he slipped because of the wind and also because he felt faint toward the end of the walk.
notes that the video does not show the entire fall and that the acrobat might have survived partly because the fall was less than reported. Regardless, it still must have been a long fall to the rocky ravine below.