Chek Lap Kok tested its Y2K-readiness yesterday in the first 'live' exercise involving passengers on 31 flights from 14 airlines. Three flight delays were reported but the Airport Authority said they were unrelated to the contingency exercise. In the first test of its kind, airport operators turned off flight information displays and check-in computers to simulate a Y2K failure. Passengers had to be checked in through manual recording and airport marshals directed taxiing aircraft with hand signals. The exercise lasted from 10pm on Wednesday to 10am yesterday. Airport Authority terminal operations general manager Ng Ki-sing said this was the first live drill involving passengers. 'These contingency drills were a good opportunity for Airport Authority staff and other business partners, including airlines and ramp handlers, to familiarise themselves with the contingency measures,' he said. The authority did not have the number of passengers involved in the exercise yesterday. Mr Ng said similar drills on a smaller scale would be carried out in the next two months and another full-scale exercise would be held in November. The emergency communications centre was also activated during yesterday's test. Mr Ng said it would serve as the command centre on the night of December 31. All of the airport's computer systems were certified Y2K-ready in August.