As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN REMOVING ELT FROM AIRCRAFT TO REPLACE ELT BATTERY, FOUND THAT SOMEONE HAD PUT THE ELT IN BACKWARDS. THE DIRECTION OF FLIGHT ARROW WAS POINTING AFT. THIS INSTALLATION IS LOCATED IN THE BAGGAGE COMPT AND THE PILOT CAN SLIDE IT OUT OF ITS MOUNT AND REINSTALLED IT BACKWARDS. (K)