As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION OF THE HORIZONTAL STABILIZER ATTACHMENT TO THE VERTICAL STABILIZER, FOUND THE 4 BARREL NUTS FOR THE FWD 4 ATTACH BOLTS WERE INSTALLED UPSIDE DOWN IN THE FITTING HOLES IN THE VERTICAL STABILIZER FITTING. THIS CAUSED DAMAGE TO THE FITTING FROM CONTACT WITH THE IMPROPERLY INSTALLED NUTS, AND A LOSS OF BOLT TORQUE.