The new Boeing procedures, as Tee Emm points out, are potentionally dangerous.
Scenario:
Capt is PF and FO PM.
FO does the preflight checks, but fails to see that the outflow valve is in MAN.
Capt calls for preflight checklist. FO duly reads and responds all overhead items, and because he has already done the drill, does not carefully recheck each item. Capt fails to crosscheck (it's not his area of responsiblility), and the valve remains in MAN.
Capt calls for After take off checklist, which now is done and read by the FO. By now he/she has "checked" that area 3 times, and in any case, the checklist only calls for checking of packs and bleeds. The valve remains in MAN.
Unlikely? I admit I don't know what procedures Helios used, but that accident happended just after the new procedures came into effect.
There simply is no challenge and response anymore. In the left seat I can read the newpaper or be asleep during most of the checklist reading. Not that I should be, but that's a fact.
I simply do not understand why?