Disparate altitude indications

[N747PW]

I have recently installed a D100 and moved the D10A to the right side. The D100 by the way has a magnificent display. Upon leaving Palo Alto I set both altimeters to 29.99"Hg and off I went. Once leveled off at around 5500' I noticed the the D100 and the D10A showed different altitudes, the D10A reading about 60' lower than the D100. This persisted even on the ground (although only 50' difference) and both instruments come off the same static source. Is this normal? Any comments?

Pat

 

[dynonsupport]

Each unit is calibrated here at the factory and neither unit should be off by that amount, However, if they were each off by 20-30 feet in opposing directions (which is a reasonable amount) you would see this effect too.

One way to determine which of the EFIS(es) are off is to compare the altitudes the EFISes report with a known airport elevation. Take care to set the baro accurately when you do this, since a setting that is off by even a hundredth may alter the reported altitude.

There is a single point altitude adjustment setting that you can make use of to correct the disagreeing altitudes. This can be found in SETUP, then ALTADJ. If you do find that one EFIS is off by 50-60 feet an the other is dead on, though, you can also elect to send the one that is very out of spec back to be recalibrated.