Why would any experienced pilot attempt this maneuver without sufficient altitude (and more airspeed in advance of the climb)? It appears that another 300-300 feet would have provided the safety margin. The pilot was Guenther Zimmer, a 74 year old and experienced. The accident took place in Belarus airshow in what looks like a Hughes MD 500 helicopter. A 2nd video shows the expert but risky low altitude maneuvers which preceded this accident. The audio of the 2nd clip contains the sound of gusting wind conditions. Given the pilot's age, it might be possible that he became momentarily disoriented or lightheaded during the loop.