What was found
EICAS SMOKE CREWREST FLIGHT DECK ANNUNCIATED SHORTLY AFTER TAKEOFF WITH CORRESPONDING SMOKE ALARM IN THE FLIGHT DECK CREWREST AREA. THERE WAS A PUNGENT ODOR BUT NO VISIBLE SMOKE. THE ALARM WENT OFF AFTER APPROXIMATELY TWO MINUTES. THE ODOR RETURNED DURING DESCENT WITH NO ALARM. LANDED NRT WITHOUT INCIDENT. OPERATED AIR CONDITIONING SYSTEM AND SMOKE DETECTORS WITH NO FAULTS NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION.