Daredevil businessman Zef Eisenberg may have started braking too soon in the moments before he died while attempting to break a speed record in a Porsche 911 Turbo, an inquest heard.
The 47-year-old was trying to prove he had created the world's fastest Porsche when he was killed in a crash at Elvington Airfield, near York on October 1, 2020.
An inquest in Northallerton heard Mr Eisenberg was trying to break a number of land speed records in the "extensively modified" car.
As he was finishing the last attempt of the day, his customised vehicle overturned at high speed and he suffered multiple traumatic injuries, dying at the scene.
The hearing was told Mr Eisenberg had asked for a braking parachute, designed to slow the car down, to be fitted to the vehicle as he created his own "bespoke design".
A statement from race marshal Graham Sykes said the father-of-two had successfully used it throughout the day.
But on the final run of the afternoon, Mr Sykes said as the parachute deployed, "the car began to lift as though air had got under it".
He said he believed Mr Eisenberg had "got the sequence wrong" and applied the brakes before the parachute had fully deployed.
The inquest heard this can cause the car to become "unstable" and lose control.
Mr Sykes said: "Sadly I feel driver error caused this tragic accident."
He added Mr Eisenberg had been a "well-known and much respected driver within British motorsports" and described his death as a "truly tragic incident".
Malcolm Pittwood, appointed by Motorsport UK as the attempt coordinator on the day, said Mr Eisenberg was trying to break national speed records for a flying start and standing start.
But he was also hoping to show he had created the world's fastest Porsche for "bragging rights" on social media, Mr Pittwood said, adding that achievement would not be recognised by Motorsport UK.
He told the inquest: "Zef had in his mind that he was able to drive the world's fastest Porsche motor car and he wished that information to be recorded."
Mr Eisenberg had already survived Britain's fastest motorcycle crash at the same airfield in 2016 when his turbine-powered motorbike failed to stop at the end of the runway.
The incident saw him break bones in his legs and pelvis - which meant he had to learn to walk again.
The former teenage bodybuilder from north London had made his fortune with the Maximuscle fitness brand of protein powder, eventually selling to pharma giant GlaxoSmithKline and moving to Guernsey.
An ultra-speed motorbike racer, in the past decade he had amassed more than 90 land speed records on two wheels and four.
After five years of intense work on a powerful bike, he set a new Guinness World record for the fastest turbine bike in the world at 234.01mph.
He underwent gruelling rehabilitation after the devastating 2016 crash and exactly a year later he was competing again on the rebuilt bike.
His enthusiasm for motor sport led to presenting the ITV show Speed Freaks, focusing on the design, build and engineering of extreme cars.
Following his death, Mr Eisenberg's family described him as "a true genius with unique talents".
The inquest is set to resume at a later date.
