Originally Posted by
fernytickles
Tee Emm - oooh ya, that sounds excruciatingly painful! Was the reaction part of the SOPs or a knee jerk response?
With 20/20 hindsight,
that crew should have first established that the cabin altitude could NOT be controlled before commencing the E D. The 'SOP' on the 737 is to select manual and CLOSE the outflow valve. Then, if the cabin cannot be controlled, down you go. It sounds as if the auto pressure controller had 'gone awol' and the manual control was 'doing the job', in which case they had the option of continuing in manual. Certainly if it is ONLY the auto control that has failed, whacking the valve closed and descending could produce a really fat little aeroplane as well as some broken ears and sinuses.
I have had one 'run-away' pressure controller where the pressure was controllable in manual. That is hard work for the F/O during the descent phase and it is worth thinking about what you need to do.