As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THERE IS A BURNING SMELL DUE TO PACK L (WHEN BLEED AIR DEMAND CHANGES).(<P>C/W CONDITIONAL INSPECTION SMOKE/ODOR IN FLIGHT DECK, FOUND CONTAMINATED RECIRCULATING FAN FILTERS REF AMM 05-5-50-200-801. REPLACED ALL RECIRCULATING FILTERS IAW 21-26-00. NO FURTHER DEFECTS NOTED.</P>)