As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PLASTIC BURNING SMELL DETECTED BY FA AND PASSENGERS AROUND ROW 5-6 DURING PUSHBACK. COULD NOT FIND SOURCE. RETURNED TO GATE<[01] INSPECTED CABIN AREA FWD CARGO AREAS PER AMM05-51-56 NO SMELLS OUT OF ORDINARY W/#2 ENGINE RUNNING PACKS ON . UNABLE TO DUPLICATE.