As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE DEVELOPED VIBRATION ON TAKEOFF. AFTER LANDING AND MAG CHECK, LT MAGNETO DEAD. DISASSEMBLY FOUND DISTRIBUTOR GEAR WITH EIGHT TEETH MISSING. FOUND ALL TEETH IN MAGNETO HOUSING. MAGNETO DISTRIBUTOR GEAR DATED 9-13-91 O/H BY MIDSTATES AIRCRAFT ENGINE, TULSA, OK. SERVICEABLE TAG W/O NR 910519.