Currently, the older single headed air bridges at terminal 1 have a series of stairs leading down to them. These are the original stairs from the terminal’s opening in 1986.
Over the next few years, these steps will be replaced by ramps and lifts to improve passenger’s experience. Additionally, the single headed air bridges will be replaced by dual head air bridges to facilitate faster turn around times.

“Design is well underway, and construction will commence no later than February 2020 and will be delivered in stages” says Perth Airport CEO Kevin Brown. Each gate will be decommissioned for about 4 to 6 months as a result.

Original Article: https://www.perthairport.com.au/Home/corporate/articles/2019/09/03/03/18/airport-central-upgrade-ramps-up