As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 4742 - DURING CLIMB, THE CREW NOTED THE FIRST OFFICERS ALTIMETER LAGGED BEHIND THE CAPTAINS AND STANDBY ALTIMETERS BY 700-800 FEET. THE CREW RETURNED TO BOS AND LANDED WITHOUT INCIDENT. BOS MAINTENANCE REPLACED THE FIRST OFFICERS ALTIMETER, PERFORMED REQUIRED PITOT STATIC AND FUNCTIONAL CHECKS AND RETURNED THE AIRCRAFT TO SERVICE. (M)