Originally Posted by
RedGritty
Isotope Toast asked:
"Do we know he flipped the switch from CVR data? "
There's no data on the CVR, just separate audio recordings from each pilot's headset microphone and from a general microphone in the instrument panel.
The operation of that guarded cockpit-door switch might not produce much sound at all, it may be unlikely to be audible at the co-pilot's headset microphone or at the instrument-panel microphone.
I've not read of the CVR recording including the sound of the door-open request or override audio-alerts. Either the investigators felt this was not sufficiently important to include in their briefing or perhaps the sound was inhibited by prior movement of the switch to the "lock" position.
The FDR records data including (I believe) some switch activation relating to flight controls. But, so far as I know from what I have read, it does not include the operation of the cockpit door lock/unlock switch. The FDR memory unit has not yet been found anyway.
It does look like the article you refer to (and quite a few others) is very poor quality as you say.
It is not what was
on the CVR recording - it is what is
NOT on the CVR recording. There are no buzzer sounds from entering the correct code nor the continual alarm from entering the emergency code. Therefore, as the captain was trying to get in with the assistance of the cabin crew one has to assume that the override switch had been activated muting both the buzzer and the alarm. As the period was 8 minutes and the override (apparently) has a 5 minute time out the override would have needed to be operated at least twice which falsifies hypotheses about an incapacitated first officer.