The north and south runways at Chek Lap Kok began operating round-the-clock for the first time yesterday, just two days after removal of the last of the wreckage of the crashed China Airlines jet.
Incoming flights will land on the north runway where the instrument landing system is more sophisticated than the south runway, which will accommodate outgoing flights.
Noise pollution complaints have increased since the north runway was partially opened on May 26.
A Civil Aviation Department spokeswoman said noise levels under the new flight paths conformed with forecasts.
She said the department would try to minimise impact on residents, especially between 11pm and 7am.
The south runway was closed for eight days after a China Airlines McDonnell Douglas MD-11 crashed and overturned while trying to land on August 22.