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.
Flight International 15-21 July 2014 has just published extracts from a an Irish investigation into a Ryan Air 737-800 pressurisation problem where the aircraft was incorrectly configured for take off and which was missed by the crew conducting the after take off checklist. According to the FI article, the crew also missed subsequent checks of the pressurisation at 3000 ft and 10,000 ft and the oversight was not discovered until 18,000 ft. Inquiries by the Ireland Air Accidents Investigation Unit found that during the after start checklist, the captain responded "packs off" when the first officer called the after start checklist.
While the before start checklist requires the air conditioning packs to be off, the after start checklist demands a "Packs Auto." The first officer did not query the error. In response, Ryan Air has introduced a procedural change following the incident, requiring the PM to verbalise cabin pressure gauge readings rather than simply call "check" during the climb. The inquiry is recommending that this change be introduced by all carriers.
In the actual AAIU report there is a interesting comment concerning an obvious flat cockpit gradient. That presumably referred to the habit of the first officer addressing the captain as "Mate" on several occasions during the pressurisation problem and taking precipitate actions without apparently first coordinating with the captain
Talk about re-inventing the wheel. The check of the cabin pressurisation instruments was always part of the after take off checklist scan from the introduction of the first Boeing 737-100 in 1968 until Boeing saw fit to change it a few years ago. See Tee Emm's earlier comments at Post 30.