A320: VENT SKIN VALVE FAULT
 

Just question for A320 drivers.. Why does VENT SKIN VALVE FAULT result in
a descend to FL100 or MEA if selecting Blower & EXTRACT to OVRD does NOT solve the problem. ??

Thanks

In the air ventilation system should be in closed configuration. When extract valve fails in full open position there is pressurisation leak. Selecting blower and extract to override sends additional signals to close them but if it fails you need to come down to 10000'.

as a additional note, the outflow should not be used to compensate for the leakage through the outlet skin valve, as some training captains point out. You have to descend because even if the outflow valve is capable to maintain the cabin altitude, that valve is not meant for such differential pressure

Thanks guys .. much appreciated.. :)