Things I'd like to see changed on the 737
Boeing IMHO made a fatal mistake some years back in changing the items on the original B737 after take off checklist. The original checklist first item was "Air Conditioning and Pressurisation......Set." Amplification was contained in the FCOM. It included checking the two pressurisation instruments of cabin altitude and cabin rate of climb.
Instead, Boeing changed that to: "Engine Bleeds....On and Packs.....Auto.
From personal observation of many after take off checklists I believe very few crews bother to verify the correct operation of the two vital pressurisation instruments of cabin altitude and cabin rate of climb and that is simply because it is not written in a checklist.
Random scanning in flight by either pilot of various overhead switches and instruments is not a checklist item and that is fair enough. Yet sound airmanship would dictate it is prudent to do so; especially the two instruments of the pressurisation system.
And another gripe. Having the PM challenge and reply to his own actions during the after take off checklist and with no input from the PF, is a real human factors trap, since more often than not, it results in the PF failing to cross check the PM's check list verbal enunciation/ actions. The PF can doubtless hear the self challenge and response by the PM, but does he look across and confirm for himself that all is done correctly? Maybe - maybe not. I am all for bringing back the tried and trusted challenge by one pilot and respond by the other pilot. And that is for all normal checklists. At least it is a proper double check.
The fatal accident to the Helios Airline B737 that took off in the manual pressurisation mode and outflow valve open, may not have happened if the crew had used the original Boeing 737 after take off checklist of "Air Conditioning and Pressurisation...Set" where part of that check was to observe the cabin altitude and cabin rate of climb as directed in the amplified section of the FCOM. Clearly neither pilot did this otherwise they would have seen an abnormal cabin rate of climb and be alerted to a pressurisation problem.
On that occasion it is presumed the PM did indeed challenge and respond to himself that he had "Set or verified" that the engine bleeds and air conditioning packs were operating as the first items on the published after take off checklist. But yet the aircraft took off unpressurised.
Right now, the Boeing 737 after take off checklist, which is started after flap retraction is complete (typically by 3000 feet), includes nothing about checking the cabin altitude or cabin rate of climb. As a result, these two vital pressurisation instruments are often missed by both pilots in the after take off scan.