What conditions exactly do you need for the AHRS to run down and 'unalign'? The tutorial states 2 mins to run down and the AOM says 15 mins. From what I gather from the manual the AHRS runs on DC power but when all power is switched off (both gens, avionics masters, batteries) the AHRS is still aligned even after waiting 20 odd minutes in a cold and dark situation. What am I missing??

On a similar note, it says in the manual the compass rose should count down from 180 to 0 but mine do not. It's stuck at 0 and after awhile the displays come back to normal? What am I missing?FRED

Adam, That seems to be a bug, unfortunately. It's been reported.Fred,You have to move the Air Data Computer test switch to the one or two position. The switch is on the right side console with the rest of the test switches. You'll have to flip the cover up first to access it.