As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INITIAL CLIMB, NR 2 ENGINE BACKFIRED SEVERAL TIMES. PROPELLER WAS FEATHERED AND ENGINE WAS SHUT DOWN. DURING POSTFLIGHT INSPECTION FOUND INTAKE HOSE P/N 2058D117 WAS CUT AND THE CLAMP AND INTAKE PIPE P/N 110082 WAS LOOSE FROM THE #1 CYLINDER. ALSO FOUND INTAKE CONNECTION FITTING P/N 126567 LOOSE IN CYLINDER HEAD.