As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED STRONG ODOR COMING FROM AROUND ROW 3, POSSIBLY BURNING PLASTIC. MAINTENANCE INSPECTED AND FOUND POWER UNIT DIMMER AT ROW 4A/C TO HAVE STRONG BURNING SMELL. MAINTENANCE REMOVED AND REPLACED POWER UNIT AND PERFORMED CHECKS USING AIRCRAFT MAINTENANCE MANUAL. AIRCRAFT RELEASED FOR SERVICE.