As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLT AT 25000FT STRONG BURNING PLASTIC SMELL IN COCKPIT FOLLOWED SHORTLY IN CABIN. FOLLOWED QRH AND SMELL MITIGATED BUT REMAINED UNTIL ON GROUND. NO SMOKE NOTED. INSPECTED PACK SYSTEMS FOR BURNING SMELL. MX FOUND BURNING SMELL IS FROM PACK 1. SEE LP 217821 SEQ 2 FOR DISCREPANCY AND RELIEF