As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOTS ALTIMETER AND ALTITUDE ALERTER WERE FLAGGED AND THE OVERSPEED WARNINGS WERE GOING OFF WHILE ON THE GROUND. THE ADC WAS FOUND TO BE DEFECTIVE AND REPLACED. THE SYSTEM WAS TESTED AND INSPECTED AND FOUND TO COMPLY AND TO REMAIN RVSM COMPLIANT. THERE HAVE BEEN NO PRIOR REPORTS OF PROBLEMS WITH THIS SYSTEM IN THIS AIRCRAFT. (K)