takata;
Possibly the Cabin Alt went above 9,550 feet at a rate greater than 1,800 ft/min - loss of pressure, but not decompression.
originally posted by PJ2 ...
The #1 CPC is powered by the DC ESSential bus, the #2 CPC is powered by the DC1 bus and CPC Manual Control is provided by the DC BATtery bus.
So yes, the control of cabin pressure would have been fully available with APU and even with with no APU with manual control from the DC BAT bus.
For the SATCOM to operate, it needs primary sources #1 or #2, or the APU. So the likelihood of the Oxygen Masks not being deployable in this instance seems remote?? But, wait a minute, the Cabin Vertical Speed warning could have queued in the ACARS sequence and been transmitted some time after the event, e.g. on a restart after a flameout or on APU start.
Just another angle on it.
The general idea was that they were going to "mow the lawn", and though they got side tracked by new information, to continue with their prime objective will in the end produce results. Like you, I am confident they will continue, as there are too many unanswered questions, and a lot of Euros that need accounting for.
mm43