The sheriff blamed cloud cover for Steve Hislop's death
A fatal accident inquiry has concluded motorbike champion Steve Hislop crashed his helicopter and died after the aircraft went out of control in cloud.
Mr Hislop, 41, was killed in the crash on hills near Hawick on 30 July 2003.
Sheriff Principal Edward Bowen QC said he was satisfied "on balance of probability" that no military aircraft had contributed to the accident.
He said experts were unanimous that a manoeuvre through cloud was one where "disorientation was extremely likely".
The sheriff issued his written judgment following an inquiry at Edinburgh Sheriff Court in April.
He agreed with the Air Accident Investigation Branch that it was most likely that emerging from cloud cover had caused the loss of control.
AAIB investigators said it was likely the engine had stalled slowing the rotor blades which sliced off the tail boom and sent the helicopter spinning to the ground.
Sheriff Bowen said: "The wreckage provides indisputable evidence of tail boom strike by the main rotor blades, resulting in most of the tail boom detaching in flight.
"That event makes the helicopter uncontrollable.
"For the reasons given, I am satisfied, on balance of probabilities, that Mr Hislop's helicopter crashed because of a low rotor RPM condition."
The inquiry had heard claims from witnesses that military jets had been in the area at the time.
However, the sheriff ruled they had not been a contributory factor.
"I am satisfied on balance of probability that no military aircraft caused or contributed to the crash of (the helicopter)," said Sheriff Bowen.
He described Mr Hislop as "a competent and careful helicopter pilot with a natural affinity for handling fast machines".
However, he said that emerging from cloud was difficult for even the most experienced pilot.
"The experts were unanimous that such a manoeuvre through cloud was one in which disorientation was extremely likely," he said.
"It was described as 'a very difficult manoeuvre, beyond most pilots'."
Mr Hislop, a twice British Superbike Champion, was born in Hawick in the Scottish Borders in 1962.
He recorded 11 Isle of Man TT victories and he later moved to the island to live.
He was flying from Hawick to Buckinghamshire when the fatal crash occurred.