Hi,
Just looking for clarification, what are the differences between the TWO "RAT MAN ON" - on the hyd overhead panel section, and then "MAN ON" on the emerg elec power section.
Either button will drop the RAT and run the Blue Emergency Hydraulic pump.
The "MAN ON" switch (on the electric panel) additionally brings the emergency electrical generator on line.
Also, the ram air inlet is basically closed in flight, and will be opened automatically if needed to?
You could open it manually in flight, when de-pressurised, to provide cabin ventilation without any packs.
It has to be closed on ground if there is heavy rain by pushing override on the extract Push Button, is this correct?
You are confusing two different systems.
On the ground & in heavy rain, pushing the override on the extract Push Button will put the Avionics Bay cooling system into the "closed circuit configuration" (closes the skin valves) and prevents rain water entering the plumbing.
Also when enroute and smoke in encountered both blower and extract have to be set to override I believe.
What exactly does this do?
Forces the air in the Avionics bay overboard without mixing any of it with cabin air.
If you find any of the switching confusing - then welcome to the club!
The same switch position can have opposite effects depending on another logic gate triggered by a different sensor.
The pictures on the systems pages help.