B200 Kingair Electrical System

[TSIO540]

1) I am trying to understand why the No 4 dual fed bus in the B200 has an item labelled "PROPELLER GOVERNOR" when as far as I can see, the primary, overspeed and fuel topping governors are all hydraulic/mechanically controlled; any ideas?

2) The No 1 dual fed bus has an item labelled "CABIN PRESSURE CONTROL"; if this item is lost for example in a No 1 dual fed bus failure, would it only affect aircraft (after BB1180 and BL71 onwards) that are fitted with an electronic flow control unit?

3) On the right Gen bus there is an item labelled "AIR CONDITIONER CLUTCH", if this bus is lost would the air conditioner clutch fail to the open position thus disengaging the compressor?

Thanks in advance to anyone who can help :ok:

[seilfly]

1) It could be govs' overspeed-test circuitry of the...

[ahramin]

1) This is for the test solenoid on the overspeed governer.

2) This is for the solenoids in the vacuum lines going to the safety and outflow valves, and has nothing to do with the flowpacks. If electrical power to these solenoids is lost, nothing happens in flight. The pressurization controller will still get vacuum from the system and will still control the outflow valve, and the safety valve will stay closed. All you lose is the ability to dump the safety valve.

A note on flowpacks. The old alcohol still style ones will close with a complete electrical failure, causing a complete loss of pressurization. The newer ones with stepper motors will simply stay in whatever position they were in when the power failed.

3) Yes, the clutch will fail open and no more air conditioner.

[TSIO540]

Thank you seilfly and ahramin :ok: