As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT CREW HAD BURNING SMELL IN FLIGHT DECK IN CABIN WITH PACKS RUNNING. FACT 08FEB25 20:51 PHL PERFORMED PACK 1 AND 2 TEST ON THE APU BLEED SYSTEM AND ENG 1 AND 2 IN REF TO MX GROUND RUN UP CHECKLIST ON IDLE. NO ABNORMAL SMELLS NOTED DURING TEST. OK FOR SERVICE AT THIS TIME.