As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 1819 REF ACARS MSG EMERG LIGHTS CAME ON AND WENT OFF MINUTE LATER WITH NO COCKPIT INDICATION, CORRECTIVE ACTION: PER CABIN CREW REMARKS TEST SWITCH INADVERTENTLY ACTIVATED. PERFORMED B767-400 FIM TASK 33-51-00-815-803 AS PRECAUTION. CHECKS GOOD. (8512439)