As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT FELT A POWER SURGE AND SAW FLAMES OUT THE LEFT ENGINE EXHAUST FOR A MOMENT. LEFT PROPELLER STOPPED TURNING. PILOT SECURED ENGINE, CONTINUED ON AND LANDED WITHOUT INCIDENT. INVESTIGATION REVEALED THAT THE PT BLADES WERE MOSTLY GONE. CT BLADES ARE OK. SUSPECT BEARING FAILURE IN POWER SECTION.