Must be level 77+ with a flying mount and be in Dalaran.
1 -So fly high and then into dalaran untill you get the "restricted flight area" buff,
2- Then stay where you are untill you the "restricted flight area" fades and
3 - The parachute buff appears, you must then get rid of the buff by right clicking it. You will receive no fall damage as there is none in Dalaran.
4- fall from at least 65 yards up to receive the achievement.