As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON TESTING THE EMERGENCY LIGHTS BEFORE STARTING THE APU THE LIGHTS WOULD NOT ILLUMINATE IN BOTH THE ARM AND ON POSITIONS. REMOVED AND REPLACED EMERGENCY LIGHT BATTERY PACKS, PERFORMED E-LIGHT SYSTEM OPERATIONAL CHECK. OPS CHECK GOOD AT THIS TIME. REF, AMM 33-50-00 AND 33-50-10. NR 1 EMERGENCY LIGHT BATTERY PACK. NR 2 EMERGENCY LIGHT BATTERY PACK NR 3 EMERGENCY LIGHT BATTERY PACK , NR 4 EMERGENCY LIGHT BATTERY PACK