As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FRAME CRACKED AT STATION 500C BETWEEN STRINGER 8LT & STRINGER 9LT IN CABIN, 1/4" CRACK CONFIRMED WITH MFECAT AIR CONDITIONING BRACKET INBD RIVET. REPAIRED FRAME AT STATION 500C BETWEEN STRINGER 8L & STRINGER 9L IAW EA 5310-04716 REF F FIG 3.