As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED AN IAS & EFIS COMPARITOR MESSAGE. FLAGS WERE PRESENT FOR HEADING AND IAS. AIRCRAFT RETURNED TO PHL AND LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE NR 2 AIR DATA COMPUTER. CHECKS WERE PERFORMED PER THE AIRCRAFT MAINTENANCE MANUAL AND AIRCRAFT WAS RELEASED FOR SERVICE.