AN air-conditioning maintenance company, found guilty of breaching a safety regulation after a worker plunged to his death, has succeeded in convincing a High Court judge that it was wrongly convicted. Quashing the conviction of Sime Darby Property Services Ltd yesterday, Mr Justice Bewley held that the trial magistrate had addressed the wrong test in coming to his findings. The judge refused to order a retrial, saying the Crown would not be able to secure a conviction with the available information. Sime Darby had denied failing to ensure safe access to a construction site and was fined $48,000 by magistrate H. H. Tam. On June 16, last year, Lam Hoi-chuen and Kong Wai-hang were assigned to inspect the cooling towers of the air-conditioning plants on the roof of a two-storey building in Tsuen Wan. To gain access to the towers, they went out of the window of the recreation room on the top floor and climbed up a metal cat-ladder to the roof, and walked along a concrete path which was 1.15 metres wide with no guard rails. They had to cross a narrow wooden plank before getting to the cooling tower. After they had worked at the cooling tower for about an hour, it began to rain and they went for shelter. But when Mr Kong came down, he found Lam lying unconscious on the floor of the recreation room and a hole on the asbestos roof directly above him. In finding Sime Darby guilty of the offence, the magistrate was satisfied that the safe access to the cooling towers on the roof of the building had not been properly maintained. But, on appeal, counsel Andrew Macrae argued that his client was not charged with failure to properly ''maintain'' the access but with failing to ''provide'' such safety measures.