Originally Posted by
chemical alli
recently our company went through the same problem with the 767 as the systems are the same
Be careful. The systems are not the same. On the B767 you can turn off both recirc fans and all you get is an increase in fuel flow as the packs go to max mode and take more air from the engines.
On the B757 the right recirc fan is the same, but the left recirc fan is used as the extract fan for the fwd equipment cooling system. Turning it off will produce equip cooling messages, and open the exhaust valve to induce flow in the system. This fan is no-go for ETOPS flights.