As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR - CREW REPORTED AN ELECTRICAL SMELL IN THE CABIN FOR A FEW MINUTES AND THEN THE SMELL DISSIPATED. RECIRCULATION FAN STATUS MESSAGE APPEARED AT THE SAME TIME. FLIGHT LANDED LHR WITHOUT INCIDENT. DEFERRED LOWER LEFT RECIRCULATION FAN INOPERATIVE PER MEL. REPLACED LEFT LOWER RECIRCULATION FAN AT JFK ON 03/28/2012. SYSTEM GROUND CHECK NORMAL OPERATION.