As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PRE-FLIGHT, THE CREW NOTED THAT THE PILOTS ALTIMETER AND ALTITUDE ALERTER WERE FLAGGED. ATTEMPTS TO RECYCLE THE SYSTEM WERE NOT SUCCESSFUL. THE CREW GROUNDED THE AIRCRAFT. AN AVIONICS TECH WAS DISPATCHED TO THE AIRCRAFTS LOCATION AND DETERMINED THAT THE ADC HAD FAILED. THE ADC WAS REPLACED. THE SYSTEM WAS TESTED AND INSPECTED AND FOUND TO COMPLY WITH FAR 91.411, PART 43 AND TO REMAIN RVSM COMPLIANT. (K)