Airline passengers will face delays and some residents around Perth Airport will suffer more noise over the next six months because one runway will be closed for repairs.
The airport is undertaking what it terms "essential maintenance and improvements" to its shorter cross runway, referred to as 06/24.
A similar upgrade was completed for the main north-south runway 03/21 three years ago. The airport's two runways cross and cannot be used at the same time.
However, depending on wind conditions, they can be used alternately to speed up landings or takeoffs.
Runway 06/24 lies in a north-east/south-west direction and will reopen in March.
The closure will increase delays at the airport, especially during peak times of mid-week early mornings and late afternoon.
It will also add to the operational challenges for pilots.
During summer, there are severe winds across the main 03/21 north-south runway, requiring the use of the cross runway 06/24.
For residents to the north and south of the airport there will be more traffic during the closure and therefore more noise, though for residents to the north-east and south-west there will be a respite.
Perth Airport said the works were being done to ensure "the safe operation of aircraft and to minimise potential disruptions to flights in the future".
During the works, two-thirds of the cross runway will be rebuilt and overlaid with a new asphalt surface.
Works will stop for two weeks over Christmas but the cross runway will remain closed during this time.
Perth Airport is in the final stages of planning for a third, parallel runway that will serve its needs well into the future.
That runway is due to be built to the east of Horrie Miller Drive and the giant Coles and Woolworths warehouse complexes in mostly vacant land.
The airport is having the most far-reaching infrastructure upgrade in its history with $1.75 billion committed for terminals, taxiways and freeways to be completed over the next three years.
A third runway will add $480 million to that bill.
Perth Airport is sending out brochures to all affected residents explaining the works program.
It has also set up an information line on 1800 933 733 that can be called between 9am and 5pm, Monday to Friday.