Difference Between BAT EPU and DCT/BAT switch on AS350
 

Greetings,

Anyone got any idea what the difference is between the BAT EPU and DCT/BAT switch on the AS350 center console is. I'm specifically looking at a B2, but B3's appear to have the same setup.

In the B2 flight manual I have there is only 1 Bat/EPU switch. The Bat automatically cuts in and out depending on whether the EPU is connected. I've got the Nemeth Designs AS350 B3 model for FSX and it appears that the DCT/BAT switch has no function at all. Anyone got thoughts on this? Google searches don't appear to contain the info I need, but an up-to-date flight manual for a B2 or B3 may.

Thanks,
Ian

In normal operation, the "BAT EPU" and "BAT/DCT" (or however the second switch is labelled) are treated as one switch, I press/engage/disengage both simultaneously. The BAT EPU controls all busses; the BAT/DCT only powers instrument panel and console switch lights without everything else. If I wanted to check switch position, altimeter etc prior to start, I would engage only that button.

Connecting an external electrical power source energizes all busses excepting the aircraft battery and generator once you engage the BAT EPU switch. The aircraft will run on the external electric power until disconnected/depleted. One can't engage the generator or battery if the external power relay is active.

Okay, I think that makes sense now. So basically (from the perspective of the pilot), powering the instrument panel and center console can be done with the BAT/DCT switch, but to start and do anything else the BAT EPU switch must also be engaged. If the EPU is actually plugged in then you will get the GENE and BATT warning light until it is unplugged. Out of curiosity (not that anyone would do this) does anything happen if you turn off the BAT/DCT switch in flight?

Nothing happens.

350 Power
 

"Devil 49 - Nothing happens"

Well it depends on what consumers are on that bus. In some aircraft it may have been modified to include ancillary items - frequently on VEMD B2/B3's this is the case depending on required mission eg. EMS.

Alright, thanks guys.