THE DTSB
The DTSB determines the Probable Cause of this accident to not be Pilot Error, in that the accident pilot was on assignment for the news station and did fly a flight profile which was normal and customary for this aircraft in this situation. The ADSb data shows an altitude of over 800 feet above ground level, and a significant forward speed of approximately 12 knots indicated airspeed as corrected for winds. The data was captured just before the accident. The HEIGHT / VELOCITY ENVELOPE data for this specific Eurocopter AS 350 B2 suggests that there was more than ample available energy available in order to enter a standard emergency Auto Rotation from this position, therefore the accident helicopter was not in flight at an altitude too low to recover. The specific order of events that occurred very rapidly are: 1) The pilot received an audible intermittent RPM overspeed warning, as manifested by the high rotor horn which is set to come on at 410 RPM, indicating an uncommanded engine RPM has suddenly increased significantly. 2) The accident pilot responded properly by increasing collective, which should have added additional load to the engine and caused a reduction in actual turbine RPM. 3) This action caused a brief aircraft nose up condition, at which time the engine shut down completely, and the pilot was forced to aggressively lower the collective in order to preserve rotor RPM. The solid low rotor RPM warning is heard as rotor RPM falls below 360 RPM but then silences as proper Auto Rotation RPM is reestablished. 4) The low rotor RPM warning is heard again just before the impact, likely as the accident pilots normal procedure to arrest the descent to the selected landing point. The entire sequence took a very few seconds from first presentation until impact. The accident pilot attempted to maneuver to avoid power lines and ground vehicles and did impact to the side of a large shipping container, whereupon the non-crash worthy fuel tank broke open, and a fire began. The emergency Auto rotation landing to that location was likely very survivable if it had not been for the immediate resultant fire as raw fuel escaped the breached non crash worthy installed fuel tank.