As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MGM - FLT 3479 - EN ROUTE FROM DFW TO SAV, RECEIVED AHARS BASIC MODE MESSAGE AND FIRST OFFICERS INSTRUMENTS WENT BLACK. BOTH ALTIMETERS READING INACCURATE DATA DIVERTED TO MGM. NO CFR OR EMERGENCY DECLARED. MAINTENANCE REMOVED AND REPLACED AHARS UNIT IAW EMB MM. OPERATIONAL CHECK WAS GOOD AND AIRCRAFT WAS RETURNED TO SERVICE. (M)