A320 Hot Air Pressure Regulating Valve Failure
Hi everyone
In the event of a failure of the A320's Hot Air Pressure Regulating Valve in the closed position, DSC-21-10-40 P 2/2 states the following:
"Optimized regulation is lost. Trim air valves are driven to the fully closed position. Pack 1 controls the cockpit temperature to the selected value and pack 2 controls the cabin temperature (FWD and AFT) to the mean value of the selected temperatures."
My question is, how can an individual pack supply a specific zone given all zones are supplied from the mixer unit, itself supplied by both packs?