As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOUND (BRACKETT) AIR FILTER ASSEMBLY (NR-BA-2405) INSTALLED BACKWARDS. THE MESH SAFTEY SCREEN WAS AT THE FRONT OF THE FOAM FILTER, AND THE INLET GRID WAS INSTALLED AT THE BACK OF THE ASSEMBLY. INSPECTED ONE OTHER FILTER ASSEMBLY ON LIKE AIRCRAFT AND FOUND IT WAS ALSO MISINSTALLED.