As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DESCENT INTO LWM, LEFT ENGINE STARTED BACK FIRING WHEN THROTTLE PULLED BACK. MAINTENANCE FOUND NR 1 AND NR 3 CYLINDER HEADS CRACKED. MAINTENANCE REPLACED NR 1 AND NR 3 CYLINDERS, RUN UP AND OPERATIONAL CHECK NORMAL. NO FURTHER DEFECTS NOTED.