Hi, when i put battery on, ground power on, IRS switches to NAV, it starts beeping forever and other NAV switch has ON DC light, and both IRS switches have flashing ALIGN text. Bat discharge light is not on, and i cant understand what im doing wrong since this has worked to me, even starting APU and setting APU GEN on wont help.

E: Oh just forgot but standby power.. lol.

What about stand by power bus and bus transfer swithes?

Right IRS might not be connected to AC power source and this noise alerts ground crew that a battery drain condition exist.

 

Oh, just noticed the your edit.

Edited August 26, 201213 yr by rsvit