Barry Dodd, 70, died from multiple injuries following the crash in Aldborough, near Boroughbridge, North Yorkshire on May 30, 2018.
Witnesses described seeing the Bell 206B helicopter, commonly referred to as a jet ranger, climbing into low level cloud before spinning anticlockwise and then descending rapidly to the ground, crashing into a rapeseed field and bursting into flames, at around 1.20pm.
Joiner Scott Wilson, who was working at a nearby property on the day, said: "The helicopter seemed to be struggling from side to side.
"It didn't seem to be happy, I was concerned because it was moving from side to side.
"It carried on going and then all of a sudden it stopped and span around anticlockwise and then stopped itself.
"The nose went up and it basked to the left and then zoomed towards the ground.
"It was virtually horizontal and then it touched the ground."
Emergency services rushed to the scene, however the inquest heard Mr Dodd died instantaneously in impact.
The inquest heard how Mr Dodd had part-owned the helicopter with his friend and neighbour Richard Menage for 14 years.
Mr Menage said: "Barry was very cautious when it came to flying. He was always compliant with his testing and meticulous with pre-flight safety check and would err on the side of caution."
Both men had learnt to fly at Multiplex in Leeds.
Mr Dodd had accumulated 250 flying hours. He had last flown the helicopter 77 days before the accident.
On the day in question, he had planned to take the helicopter for its annual check at Walton Wood Airfield in Pontefract, and had gone to Mr Menage's house, where the aircraft was kept at around 9.30am.
He decided not to fly due to poor visibility, but returned a couple of hours later when the weather had improved and completed the relevant safety checks.
He departed at 1.17pm for the 25 minute trip to Pontefract.
But just minutes into the flight Mr Dodd appeared to be "struggling" and the helicopter began climbing into the clouds.
Air accident investigators described how challenging this would have been for a pilot.
Inspector Robert Clements said: "It is a very disorientating experience. Mr Dodd would have practised this during training but in training you know it's coming and you are mentally prepared but when it happens for real, it is very challenging.
"It can be so disorientating that the pilot would not know which way was up."
Investigators explored five possible explanations as to why the crash occurred, including disorientation, distraction, avoiding action, a minor medical condition and a minor technical fault, but could not say "with any certainty" why the helicopter pitched up.
Mr Clements said: "We do know its very challenging to fly in cloud, especially when you are not used to flying in these conditions."
No defects with the helicopter were found.
Mr Dodd, who was awarded a CBE in 2014, owned an international manufacturing company and served as North Yorkshire's representative to the Queen.
North Yorkshire County Council said Mr Dodd was a successful entrepreneur and philanthropist who had a passion for helping others in business.
He was also serving as chairman and pro-chancellor at the University of Hull, and chairman of the joint Hull York Medical School.
The inquest continues.