REGIONAL JET ACFT HAS ALTIMETER CHANGE UNCOMMANDED. ALTDEV RESULTS.

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AFTER ALL BEFORE TKOF CHKLISTS WERE COMPLETED; FLT DEPARTED LEX RWY 3. TURN TO THE N WAS INITIATED WHILE CLBING TO FILED ALT OF 10000 FT. AS AUTOPLT BEGAN TO CAPTURE ALT ON FO'S INSTS; CAPT REALIZED A DISCREPANCY IN ALTIMETER SETTINGS. AT THAT MOMENT LEX DEP ALSO CALLED TO QUESTION ALT. FO'S ALTIMETER WAS CORRECTED AND DSCNT WAS IMMEDIATELY EXECUTED TO CORRECT ALT. LEX SUPVR WAS CONTACTED VIA TELEPHONE ON GND AFTER ARR TO CVG. OCCURRENCE WAS CAUSED BY AN UNCOMMANDED CHANGE OF ALTIMETER SETTING ON FO SIDE FROM 30.27 INCHES TO 29.35 INCHES. ACFT IS EQUIPPED WITH EFIS SYS. UPON DISCUSSION WITH COMPANY AVIONICS DEPT; CAPT AND FO WERE TOLD THAT THIS OCCURRENCE HAS HAPPENED BEFORE AND IS POSSIBLE DUE TO MOISTURE OR ELECTRONIC SPIKES. THE EVENT WAS DUPLICATED ON THE GND IN CVG. SUPVR AT LEX DEP RESPONDED THAT HE WAS 'SATISFIED ON HIS END' AND THAT NO PROBS HAD RISEN. THIS IS THE FIRST I HAD SEEN THIS PROB WITH AN ELECTRONIC ALTIMETER; ALTHOUGH I SINCE HAVE HEARD OF OTHERS HAVING THE SAME PROB. I SUGGEST CHANGE IN CHKLIST FOR ALTIMETER XCHKS AFTER SECOND GENERATOR COMES ON LINE. THIS WILL ALLEVIATE THE ELECTRONIC PROB BUT MANUFACTURER SHOULD ADDRESS THE MOISTURE PROBS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THE ACFT IS THE CANADAIR REGIONAL CARRIER. IT IS AN ALL ELECTRONIC ACFT AND WHEN THE LAST OF THE GENERATORS COMES ON LINE IT PUTS A SPIKE ON THE LINE AND THIS CAUSES THE PROB IN ALTIMETER. IT SEEMS TO BE ALWAYS ON THE FO SIDE AND THE ALTIMETER ALWAYS GOES HIGH. RPTR'S COMPANY HAS PUT OUT AN OPS NOTE BUT HAS NOT MADE ANY CHKLIST CHANGES. THIS IS IMPORTANT TO THE RPTR AND HE ALSO FEELS THE TRAINING DEPT SHOULD TEACH ABOUT THE PROB IN GND SCHOOL. COMPANY APPEARS TO BE WORKING WITH MANUFACTURER OF THE ACFT AND WITH COLLINS TO ATTEMPT TO SOLVE THE PROB BUT RPTR FEELS NOT ENOUGH HAS BEEN DONE TO ALERT THE PLTS TO FREQUENTLY XCHKING THE ALTIMETERS. RPTR IS ALSO CONCERNED BECAUSE LEX TWR CTLR SAID NO PROB BUT INDICATED HE HAD CALLED ANOTHER FACILITY.