As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, THE FIRST OFFICER'S ALTIMETER OFF FLAG AND THE ALTITUDE ALERTER OFF FLAG CAME INTO VIEW. FLIGHT RETURNED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE AIR DATA COMPUTER AND ALTITUDE ALERTER INDICATOR, OPERATIONAL CHECK OK.