Four people were injured after a police officer lost control of his car and crashed into another vehicle.
PC Kraig Atkinson's high-performance Nissan became airborne after coming over a hill "at inappropriate speed".
The vehicle then struck a fence and overturned before bouncing back into oncoming traffic and hitting another car.
More than 20 yards of fence and hedging was destroyed and gouge marks were left in the tarmac before the car came to rest between a footpath and a field.
Atkinson's girlfriend and three people in the other car were hurt in his off-duty smash on the B751 near Gatehead, Ayrshire.
The 21-year-old Strathclyde Police officer was found guilty of careless driving and given a £1000 fine, plus nine penalty points, at Kilmarnock Sheriff Court on Wednesday.
Constable Angus Murphy, a traffic officer, told the court there was evidence Atkinson's extensively-damaged vehicle had "come over a hill crest at a speed that was inappropriate".
While being questioned in hospital, Atkinson told a colleague: "I think I was possibly driving too fast."
Atkinson, whose address was given as care of Kilmarnock police office, had denied driving dangerously and at excessive speed for the conditions in February 2011.
After a two-day trial, Sheriff Elizabeth McFarlane convicted him of the lesser charge of careless driving.
A spokeswoman for Strathclyde Police said: "Following the outcome of criminal proceedings the circumstances will be considered by the Deputy Chief Constable."
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