As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE AIRCRAFT WAS GROUNDED. FLIGHT ATTENDANTS REPORTED ACRID SMELL DURING FLIGHT. PASSENGERS ALSO COMPLAINED OF SMELL. ACCOMPLISHED AIR QUANTITY CARD 05-96-70 FOUND RECIRCULATION FAN AIR FILTERS CLOGGED. REPLACED HIGH EFFICIENCY HEPA FILTERS IAW MM 21-25-02.