This is why I always check the 'air con and press' system in the climb, passing FL100 and FL200, no matter how automated the system is.
Agree. The original 737 after take off checklist included the item "Air Conditioning and Pressurisation .....Check."
I think it was after the Helios accident, Boeing changed it to: 'Packs....Auto.
Bleeds....On. The former Air Con and Pressurisation was removed.
I have always believed that was a retrograde step. On the former check list , the amplified section referred the crew to confirm the cabin altitude was normal and the pressurisation needle indicated the aircraft was pressurising.
Now that has vanished, in the simulator we see in the after take off scan and checklist,the PM challenging himself and replying to himself the items Bleeds on and Pack Auto and neither pilot looks at the pressurisation instruments because it is not mentioned in the check list anymore.