What was found
DCA - THE EMERGENCY LIGHTS FAILED THE OPERATIONAL TEST. MAINTENANCE REPLACED THE LEFT HAND, MID CABIN EMERGENCY POWER SUPPLY UNIT. OPERATIONALLY CHECKS OK.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
DCA - THE EMERGENCY LIGHTS FAILED THE OPERATIONAL TEST. MAINTENANCE REPLACED THE LEFT HAND, MID CABIN EMERGENCY POWER SUPPLY UNIT. OPERATIONALLY CHECKS OK.