An employee stepped out onto a maintenance stand platform from the crew entry door area of an aircraft. The employee was standing with his right foot on the first step of the maintenance stand. As he turned to go back into the aircraft, he tripped and fell halfway down the stairs of the stand, exiting through the side railing of the stairway and falling approximately 8 feet to the ground, striking equipment as he fell. The employee suffered six broken ribs, a broken collarbone, a dislocated elbow, and a collapsed lung.