The vehicle crashed into a highway barrier in Mountain View, California.
But the report does not draw an explicit conclusion about the cause of the crash.
In the days after the crash, Huang's wife Savonne said her husband had complained about the system not working properly near the area where the crash occurred.
Federal investigators did not provide a probable cause of the crash, and the inquiry is ongoing.More news: Karnataka: Protests hinder screening of Rajinikanth’s film ‘Kaala’
Tesla wouldn't say if the system performed as designed.
"Tesla Autopilot does not prevent all accidents - such a standard would be impossible - but it makes them much less likely to occur", the blog post reads. The Model X sustained major damage, causing the front end to separate from the rest of the auto.
Bystanders removed Huang from the auto before its battery pack caught fire, and he was transported to a nearby hospital where he died later from his injuries.
The NTSB report also indicates that not only did the driver not have his hands on the steering wheel in the final six seconds before impact, but there was "no precrash braking or evasive steering movement detected".
The Tesla was following a lead vehicle and traveling about 65 miles per hour, eight seconds before the crash.More news: NASA's Curiosity rover discovers organic matter on Mars
At 7 seconds prior to the crash, the Tesla began a left steering movement while following a lead vehicle.
The report noted that at four seconds before impact, Model X was no longer following a vehicle in front and began to speed up. In their report, the NTSB says Huang's Autopilot system sped up to 70.8 miles per hour (from 62 mph) three seconds prior to the crash, rather than slowing down or coming to a stop. That left the vehicle in a so-called "gore area", a triangular region of pavement between highway lanes and an exit ramp. A Tesla website says its vehicles have "full self-driving hardware". Four seconds before the crash it was no longer following the lead vehicle, the NTSB said.
Questions have been raised about the Tesla autopilot system's ability to detect stopped or stationary objects in other crashes. Drivers are expected to keep their hands on the wheel and engaged at all times when the feature is activated. The woman sustained minor injuries. NTSB, along with the National Highway Traffic Safety Administration, a regulatory agency that can seek recalls and fine automakers, are investigating that crash.
Tesla, which is said to be one of the shorted stock in the United States, saw a 9.74% spike on Wednesday following CEO Elon Musk's announcement at the company's annual meeting that Model 3 production was on track, and that the company should hit its production goal of 5,000 cars per week this month.
The impact killed the Tesla's driver and severed the electric crossover SUV.More news: Warriors beat Cavs to close in on second straight title
Tesla said earlier that "the reason this crash was so severe is because the crash attenuator, a highway safety barrier which is created to reduce the impact into a concrete lane divider, had been crushed in a prior accident without being replaced".