Interesting. That last para, if relevant, would mean that the signal to close the outflow valve and pressurise the a/c would not be there either, with a DCPCS system. Not being a techie I do not know whether a failure after t/off of the a/g 'air' signal would actually open the valve or leave it closed. Any techs know?
This 'failure' would, I presume, be instantly identifiable on the FDR, since several other circuit functions would change also. So, unless the crew were actually monitoring the cabin altitude, it could all have gone un-noticed. Do we know at which point the 'horn' was audible on the R/T?
Last edited by BOAC; 25th Jan 2006 at 12:18.