A B777 EMER EXIT LIGHTS WERE FLICKERING. THE FLT CREW CHANGED ACFT AND THE EMER EXITS LIGHT FLASHED ON THE NEW ACFT ALSO.

Narrative

AT GATE; WHEN CREW (3 PLTS; 11 FLT ATTENDANTS) BOARDED ACFT; EMER EXIT LIGHTS INSIDE ACFT STARTED FLASHING INTERMITTENTLY. MASTER EMER EXIT LIGHTS SWITCH IN COCKPIT WAS OFF. COULD NOT TURN OFF FLASHING EMER EXIT LIGHTS. MECHS COULD NOT FIND CAUSE. CREW SWITCHED TO ANOTHER ACFT. SAME PHENOMENON OCCURRED ON SECOND ACFT WHEN CREW BOARDED. SEEMED TO INDICATE THAT CREW TRIGGERED THE ACTIVATION OF THE EMER EXIT LIGHTS. CREW EXITED ACFT WITH ALL CREW BAGS ONTO THE JETBRIDGE. SECURITY PERSONNEL EXAMINED EACH CREW MEMBER BAG TO CHK IF AN ELECTRONIC DEVICE INSIDE A BAG TRIGGERED THE EMER EXIT LIGHTS SYS. NO SUCH DEVICE WAS DISCOVERED. FLT CREW INDIVIDUALLY REENTERED THE ACFT IN DELAYED SEQUENCE TO CHK EACH CREW MEMBER. 1 CREW MEMBER WAS ENTERING THE ACFT WHEN EMER LIGHT FLASHED BRIEFLY. BAGGAGE WAS CHKED AGAIN; BUT NOTHING WAS FOUND AND LIGHTS DID NOT FLASH AGAIN. NO FURTHER SYS MALFUNCTION AND ACFT DEPARTED FOR DEST. AFTER 2 HRS INTO FLT AT CRUISE; EMER EXIT LIGHTS FLASHED INTERMITTENTLY BRIEFLY FOR APPROX 10 SECONDS. NO FURTHER FLASHING OCCURRED FOR REMAINDER OF FLT. LOGBOOK ENTRY MADE AT DEST.