A fatal accident involving a Tesla Model X on Autopilot came under investigation by the U.S. National Transportation Safety Board (NTSB) in March.

The NTSB has now released its preliminary report of the accident.

After the accident, which took the life of the driver, had gathered a lot of media attention and scrutiny from the NTSB, Tesla released a detailed report of what it thought happened based on the vehicle’s data logs.

The NTSB corroborated the sequences of events leading to the crash with its own review of the recorded performance data:

  • The Autopilot system was engaged on four separate occasions during the 32-minute trip, including a continuous operation for the last 18 minutes 55 seconds prior to the crash.
  •  During the 18-minute 55-second segment, the vehicle provided two visual alerts and one auditory alert for the driver to place his hands on the steering wheel. These alerts were made more than 15 minutes prior to the crash.
  • During the 60 seconds prior to the crash, the driver’s hands were detected on the steering wheel on three separate occasions, for a total of 34 seconds; for the last 6 seconds prior to the crash, the vehicle did not detect the driver’s hands on the steering wheel.
  • At 8 seconds prior to the crash, the Tesla was following a lead vehicle and was traveling about 65 mph.
  • At 7 seconds prior to the crash, the Tesla began a left steering movement while following a lead vehicle.
  • At 4 seconds prior to the crash, the Tesla was no longer following a lead vehicle.
  •  At 3 seconds prior to the crash and up to the time of impact with the crash attenuator, the Tesla’s speed increased from 62 to 70.8 mph, with no precrash braking or evasive steering movement detected.

The report also addresses the response to the battery fire that followed the crash and the fact that the battery pack reignited days later.

The preliminary report doesn’t determine the probable cause of the accident and instead mainly lists the findings to date.

The NTSB wrote:

The NTSB continues to work with the California Highway Patrol and the California Department of Transportation to collect and analyze data, including all pertinent information relating to the vehicle operations and roadway configuration. All aspects of the crash remain under investigation as the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar crashes.​

Here’s NTSB’s full preliminary report of the accident:

View this document on Scribd

A Tesla spokesperson pointed you back to Tesla’s previously mentioned blog about the accident and declined to comment further.

Electrek’s Take

Interestingly, we already have a very good idea of what happened when it comes to Autopilot with this accident since other Tesla owners have recreated it on video.

It serves as a tragic reminder that drivers need to always pay attention when using Autopilot and be ready to take control at all time.

Aside from Autopilot, the NTSB report could actually prove useful regarding the response to the fire and the state of the crash attenuator.

More first responders need to know how to handle battery packs after they have been badly breached and I wouldn’t be surprised if the report finds that the driver would have likely survived if the crash attenuator was fixed before the crash.

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