NBA great Bryant, 41, and his 13-year-old daughter Gianni were among nine people who tragically died when the aircraft they were travelling in came down in Calabasas, California last month.
The National Transportation Safety Board (NTSB) on Friday released its preliminary findings from the January 26 crash, revealing the two engines appeared to be working at the time of impact as a piece of cut tree branch was found 30 feet from the impact crater.
It was also stated that significant components of the helicopter were located within the wreckage area and examination of main and tail rotor assemblies "found damage consistent with powered rotation at the time of impact."
The main wreckage was about 127 feet from a two-foot-deep impact crater and the helicopter's instrument panel was totally destroyed.
Prior to crashing, the 50-year-old pilot asked for special clearance to proceed into airspace that was otherwise limited to instrument-controlled flights due to a low cloud ceiling and low visibility.
During his last transmission the pilot, who had been flying for Island Express Helicopters for about 10 years, said he was climbing to 4,000 feet to get above cloud layers.
The helicopter rose to about 1,500 feet above Highway 101 but started to descend as it turned left and the rate of descent increased to 4,000 feet per minute at a ground speed of 160 knots, the report stated.
A witness said the area where the helicopter, which he saw for up to two seconds after it emerged from the clouds, crashed was surrounded by mist.
It was also noted that videos and photos taken by the public in the area of the accident depict fog and low clouds obscuring the hilltops.
Vanessa Bryant, Kobe's wife, revealed a celebration of the life of her husband and teenage daughter Gianna will take place at Staples Center on February 24.