(Recasts with likely finding by U.S. regulator)
By David Shepardson
WASHINGTON, Sept 11 (Reuters) - The National Transportation Safety Board is expected to find on Tuesday that Tesla Inc's Autopilot system was a contributing factor in a May 2016 Model S crash that killed a man in Florida while using the car's semi-autonomous driving system, two people briefed on the matter said.
The people confirmed that the system is expected be labeled a contributing factor in the crash because it allowed drivers to avoid steering or watching the road for lengthy periods. The persons declined to be identified because the NTSB conclusions have not yet been made public.
Bloomberg News reported some of the expected findings earlier on Monday.
The NTSB is also expected to find that Tesla could have taken additional steps to prevent the system's misuse and fault the driver of the Tesla.
A spokesman for NTSB declined to comment.
Tesla said in June 2016 that Autopilot "is not perfect and still requires the driver to remain alert."
Also on Monday, the family of the driver killed in the 2016 incident said the car was not to blame for the crash.
The statement from the family of Joshua Brown, released by a law firm, comes a day before the NTSB hearing to determine the crash's probable cause.
"We heard numerous times that the car killed our son. That is simply not the case," said the statement from the family, breaking its silence on the crash. "There was a small window of time when neither Joshua nor the Tesla features noticed the truck making the left-hand turn in front of the car."
"People die every day in car accidents," the statement said. "Change always comes with risks, and zero tolerance for deaths would totally stop innovation and improvements."
A spokeswoman for Tesla and a lawyer for the family, Jack Landskroner, have declined to say if the automaker has reached a legal settlement with the Brown family.
"Josh Brown was a friend to Tesla, and as his family articulated so eloquently, a passionate advocate for technology. Our thoughts are with the entire Brown family," the company said in a statement Monday.
The fatal incident raised questions about the safety of systems that can perform driving tasks for long stretches with little or no human intervention, but which cannot completely replace human drivers.
Brown, a 40-year-old Ohio man, was killed near Williston, Florida, when his Model S collided with a truck while it was engaged in the "Autopilot" mode.
In January, the National Highway Traffic Safety Administration said it found no evidence of defects in the crash. NHTSA said Brown did not apply the brakes and his last action was to set the cruise control at 74 miles per hour (119 kph), less than two minutes before the crash - above the 65-mph speed limit.
In June, the NTSB said that during a 37-minute period of his final drive Brown had his hands on the wheel for just 25 seconds.
Tesla in September 2016 unveiled improvements in Autopilot, putting new limits on hands-off driving and other features that its chief executive officer said likely would have prevented the crash death.
The family noted Tesla's continued improvements to Autopilot and said it "takes solace and pride in the fact that our son is making such a positive impact on future highway safety."
NTSB could make policy recommendations but cannot order recalls or force regulatory changes. (Reporting by David Shepardson; Editing by Jonathan Oatis and Matthew Lewis)