As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TRI - FLT 896 - EN ROUTE PIT-CLT, AT FL310, RECEIVED AN APU FIRE WARNING. THE FIRE EXTINGUISHING SYSTEM AUTOMATICALLY DISCHARGED. THE FLIGHT DIVERTED TO TRI AND LANDED SAFELY. MAINTENANCE INSPECTED THE APU ENCLOSURE AND THE TAIL COMPARTMENT. NO SIGNS OF A FIRE WRE FOUND. (M)