The crash happened in the Borders almost five years ago
A motorbike star probably lost control of his helicopter after flying into cloud, an air accident investigator has told an inquiry.
British superbike champion Steve Hislop, 41, died after crashing near the A7 in the Borders in July 2003.
A fatal accident inquiry in Edinburgh was hearing evidence from Air Accident Investigation Branch inspectors.
Witnesses have previously claimed they heard jets in the area at the time of the crash. The hearing continues.
Paul Hannant, a senior inspector at the AAIB, said radar records showed there was only one aircraft flying low in the area at the time - most likely Mr Hislop's R44 helicopter.
He said two Harrier jets had passed through the area more than half an hour after the crash.
Mr Hannant said the adverse weather conditions on the day were the most probable cause of the accident.
He said it was common for helicopter pilots to become disorientated in cloud and it was "extremely difficult" to recover safely.
Data from the global positioning system unit (GPS) recovered from the wreckage showed the helicopter had climbed dramatically and turned around shortly before crashing at 1104 BST, the inquiry was told.
Mr Hannant said it was likely the helicopter had made an emergency climb and turned back the way it came in a bid to get out of cloud.
Investigators found the main rotor blade had struck the helicopter's tail in the final stages of the flight.
"The probable cause was the inadvertent entry into cloud and attempting to recover from that," said Mr Hannant.
The inquiry heard Mr Hislop was a conscientious pilot
"It's a very alarming experience and it's very difficult to deal with."
He said that looking at all the data he believed Mr Hislop had lost control coming out of the cloud.
The inspector said there appeared to be no other contributing factors.
"It was a flight which had been well planned and Mr Hislop had waited until the weather improved, which was a responsible action to take," he added.
Mr Hannant said eyewitnesses who spoke of jets flying up the A7 were mistaken in thinking it happened at about the same time as the helicopter passed.
The inquiry was also told Mr Hislop had qualified to pilot a smaller helicopter before he took lessons in the R44.
He passed his test less than three months before he died and had been a conscientious pilot who flew "very, very well" according to his instructor.
The inquiry, before Sheriff Principle Edward Bowen QC, is expected to last another two days.