The National Transportation Safety Board (NTSB) has launched its fourth active investigation into a crash involving a Tesla, this time looking into a fatal incident on Tuesday where a Model S left the road and crashed into a concrete wall.
The agency’s investigation is centered on the battery fire that resulted from the crash. Of the other three investigations, one is also about a battery fire and the other two involve Tesla’s autopilot system.
The latest crash, which occurred in Fort Lauderdale, Fla. killed two teenagers, driver Barrett Riley and front seat passenger Edgar Martinez. A second passenger was taken to hospital.
According to Tesla (TSLA), this was a “very high-speed collision and… Autopilot was not engaged.”
The NTSB already has two active investigations involving Tesla crashes where autopilot was engaged: a crash in Culver City, Calif. in January, where a Model S plowed into the back of a fire engine; and the March crash in Mountain View, Calif. where an Apple engineer was killed when his Model X crashed into a highway barrier.
The latter incident has led to a hugely fractious relationship between the NTSB and the car-maker, which released details of its own investigations—blaming the dead driver—against the agency’s wishes.
This time round, the NTSB is examining the emergency response to the crashed Tesla’s lithium-ion battery fire. The probe is part of the agency’s attempt to “understand the impact of these emerging transportation technologies when they are part of a transportation accident,” it said in a Wednesday statement.
Similarly, the NTSB is also still investigating a battery fire that took place when a Tesla Model X crashed into someone’s garage in Lake Forest, Calif. last August.