Original Message

ADS-B data shows he left his HOGE and was in a level 1000' left hand orbit between 45-60 knots for 36 seconds before the sudden change in vertical speed to around 1000' fpm descent with a rapid left turn at the very end and vertical speed increasing to -3136 and -4480 at the last point.  Timing and rates of descent indicate an entry to an autorotation but most likely lost rpm eventually leading to a full rotor stall and sadly fell the last 100-200 feet.  The steep turns witness at the end was the last tightening of the left hand turn to end up in the shoulder area vs the main roadway, wether he still was in control at that point or the aircraft rolling in as the rotor stalled we will never know. Very sad day, great guy from everything I've heard.