A plane has been forced to turn around just before take-off because its passengers bypassed checks at Chek Lap Kok - sparking the second security probe in a fortnight.
About 100 transit passengers on a China Airlines CI652 flight from Kuala Lumpur to Taipei were sent to the departures lounge instead of the arrivals hall.
Passengers in transit must go to the arrivals hall to have their carry-on bags re-checked, but the China Airlines passengers went straight to the departures hall.
Airline staff discovered the mistake as the plane was preparing to take off at about 8.30pm on Saturday.
The flight was delayed for two hours so the bags could be checked.
Airport Authority spokesman Chris Donnolley said the body had written to the Civil Aviation Department complaining that China Airlines had breached security rules.