Originally Posted by
nzkarit
I thought there was also a connection for ground air con via the big yellow hose.
You're right, those big yellow flexible hoses would be the aircon connectors. I think they arent that common in Changi, though I do remember seeing them in KUL & BKK (Somehow recall BKK prohibits the extended use of the APU so the aerobridge has both AC and ground power connections).