Airport chiefs apologised yesterday to passengers who got hot under the collar when the air-conditioning at Chek Lap Kok was shut off. An operator's mistake caused a breakdown in the terminal at 7pm on Monday night. However, cool air delivery was fully resumed by 11pm. 'Somebody diverted from procedure and it caused a chain reaction of events,' Airport Authority spokesman Chris Donnolley said. 'It wouldn't have got unbearably hot, but you would have noticed the difference.' The shutdown followed an electricity cut last week - on the first day of the independent inquiry into the chaotic opening of the airport.