Originally Posted by
Walnut
When an a/c suffers a rapid depressurisation the initial effect is a white mist (water vapour) obscures the cabin, smoke sensors could be fooled into detecting this, however one would expect a cabin low pressure to be triggered at the same time
So is it possible that this sensor was somehow disabled or maybe its protocol to transmit the warning to ACARS was not in the time available?
Having had a rapid decompression at FL330 on an L1011 I can tell you from my own experience that there was no white mist just a loud 'woomph' sound and that, with a check on the cabin altitude, was enough to prompt us to don oxygen masks and start an emergency descent. The cause was the failure of the rear negative pressure relief valve which is some 80 cm in diameter which had a total failue around its perimeter.