Originally Posted by
Semper Amictus
If they didn't pull them down firmly, no oxygen.
If they didn't see the transparent 'balloon' bit inflating, perceived lack of oxygen !
Some reports quote passengers who pulled the masks a bit too firmly and pulled them out of the ceiling. There are also reports of some masks not dropping and flight attendants having to pull them down. My guess is that masks failing to drop might be related to no oxygen pressure - or low pressure further away from the supply - are they all on one line/ring ?