Originally Posted by
owl-attack
If all zone controls and primary pack controls fail, the standby pack controls command the packs to produce air temperature which will satisfy the average temperature demand of the two cabin zones. The trim air modulating valves will close. The flight deck zone temperature selectors will have no effect on the standby pack controls
Without reading anything but the above on this matter, I think the reason for this is that the average temperature in the two cabin zones satisfies by definition both cabin zones and most likely will thus flight deck as well. In other words, why make both cabin zones really cold and comfy and warm up front, or in reverse both cabin zones toasting and cold up front...