As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ROUTINE ENGINE RUNUP, ENGINE DIED WHEN SWITCHED TO LT MAGNETO. REMOVED LT MAGNETO. OPENED TO INVESTIGATE, AND FOUND CONTACT ASSY BROKEN IN 2 PIECES. NO OTHER. DAMAGE FOUND. INSTALLED NEW CONTACT ASSY PN M3081. REINSTALLED MAGNETO. FUNCTIONAL, TEST GOOD. THERE WAS NO APPARENT REASON FOR THE COMPONENT FAILURE. TTSN 3.9.