As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - LT PACK OFF EICAS MESSAGE MOMENTARILY APPEARED AND WENT OUT, F/A NOTICED VIBRATION NOISE ROW 20-23. RAN PACKS AND TROUBLESHOT PACK SYS IAW FIM 21-51-00-1. ALL CHECKS WERE NORMAL-PACK TEMP CONTROLLER BITE HAD NO FAULTS-OK FOR SERVICE.