I've studyed the panel operation manual over and over until I can power up the aircraft for the first time (woohoo). I use the stock flight called aircraft preparation for practice where it put you in the cold and black cockpit. What I wonder is once the cockpit has loaded and althought every equipment is in the unpower state, I can hear a humming noise of something. What is it then? I'm sure there is no other aircraft near me and the humming must come from the panel. I expect the panel in this state should be complete silent.

Are you sure that the recirculation fans are not turned on? Because they hum. :-) And I can't think of anything else on the panel that does that.Martin767 fetishistIt's a lot like life and that's what's appealing

thanks for a quick reply, yes I'm sure the recirculation fans are off, or even thought they are mistakenly left on I have turned off the main battery and APU, so there shouldn't be power left for any component. Strange isn't it?

i remember the sound would disappear if you turn the both utility bus off~~

Perhaps it's the gyro in your Standby Attitude Indicator winding down? :-hahCheers.Ian.

Actually when the main battery is switched off, the hot battery bus is still powered. Items on the hot battery bus can never be turned off, such things as the fire switches, PA and clocks. I also remember in the real sim that the standby altimiter vibrator remains on with everything else off (might be a sim thing?).

"I also remember in the real sim that the standby altimiter vibrator remains on with everything else off (might be a sim thing?)"Must be a sim thing, HP...The Vibrator is powered by the 28v Standby Bus on our aircraft.As for the clock, only the quartz crystal time base and the microprocessor time calculation circuits will be active with the Battery Switch turned off (no other functions, such as noisy(?) clockworks and displays).Finally... My notes tell me that the PA is on the Battery Bus (not the Hot Battery Bus), so it sounds like your sim needs reprogramming ;-)As for the humming... Perhaps the PNF has forgotten the words to Auld Lang Syne? :-hahCheers.Ian.

"My notes tell me that the PA is on the Battery Bus (not the Hot Battery Bus)," YEPBest Wishes,Randy J. [email protected]" A little learning is a dangerous thing"

...or to be more accurate ;-)http://members.ozemail.com.au/~b744er/767/Clock.gifCheers,Ian.

hi again tnx all for detailed explanation. To my understanding, the humming comes from some devices that cannot be turned off then?

"To my understanding, the humming comes from some devices that cannot be turned off then?"Unlikely, Marvel.Unfortunately, I cannot reproduce the humming that you hear (in my PIC setup). I suggest that you post a screenshot of your overhead panel. At least this way we can figure out if you really do have no power on the aircraft which will cause this humming. Does it only happen with PIC? (I'm thinking you may have a speaker problem).BTW, do you just have the basic PIC setup... or have you merged it with anything... or made changes to the panel in any way?Cheers.Ian.P.S. BTW, the IRS's can run on the Hot Battery Bus if the main busses lose power and you leave the IRS's switched on. The Inertial Reference Units use a piezoelectric dither motor (vibrator) to prevent possibility of "laser lock". This creates a humming noise. However the IRU's are located in the MEC, about 20 feet away from the flight crew's ears. Perhaps you have superman-like hearing? :-hahP.P.S. Do you have External Air or External Elec Power hooked up?

hi I'm using the PIC/POSKY merge and Randy's latest VFR landing view. I don't think it's from the IRS gyros nor does my headset speaker humming, since the humming start once I loaded the panel from "cockpit peperation" flight where everything should be completly in the power down state. Anyway I'm using the alternative sound set, not sure weather that's the cause, I'll try fix it.

"Anyway I'm using the alternative sound set, not sure weather that's the cause, I'll try fix it." You know come to think about it I have the same "noise" with a cold cockpit. I also use Phil's sound edit. Best Wishes,Randy J. [email protected]" A little learning is a dangerous thing"

Yup... that noise is that file that was "//" out for FS2002... I assume it's because it didn't turn off along with the stand-by bus. I have no idea how to get it to turn off along with with the electrical systems. For me, having it on with power far outways the inconvenience of hearing it when the battery is turned off.Sincerely,Phil Geddes

I have to agree with you there Phil! If I may suggest to you to include this little tidbit in the readme though? LOLBest Wishes,Randy J. [email protected]" A little learning is a dangerous thing"