As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT NR 4864 - AFTER TAKEOFF THE CAPTAIN'S ALTIMETER FAILED, THE AIRCRAFT RETURNED TO BOS LANDING WITHOUT INCIDENT. MAINTENANCE WAS DISPATCHED TO THE AIRCRAFT. MAINTENANCE REMOVED AND REPLACED THE CAPTAINS ALTIMETER AND RETURNED THE AIRCRAFT TO SERVICE. (M)