What was found
THE CAM FOLLOWER SPRING THAT IS A PART OF THE BREAKER POINT ASSY IN THE LT MAGNETO BROKE COMPLETELY OFF AT APPROX ITS MID POINT, RESULTING IN TOTAL FAILURE OF THAT MAGNETO. NOTE: THIS FAILURE OCCURRED APPROX 18 OPERATIONAL HOURS FOLLOWING AN IDENTICAL SUCH FAILURE IN THE RT MAGNETO (REPORTED 6/14/2011). THESE FAILURES OCCURRED ON MAGNETOS WITHIN THE SPECIFIC SN BLOCKS IDENTIFIED IN MSB SB2-08A AND SB3-08A AS POSSIBLY HAVING OTHER DEFECTIVE INTERNAL PARTS (CARBON BRUSH AND CAM. STRONGLY SUSPECT THAT THE SAME SUPPLIER MFG THE OBVIOUSLY DEFECTIVE BREAKER POINTS). STRONGLY SUGGEST THIS TO BE A SERIOUS ISSUE AND POSSIBLY WORTHY OF AIRWORTHINESS DIRECTIVE ACTION (CONSIDER THE 18 HOUR TIME PERIOD BETWEEN FAILURES- COULD HAVE EASILY BEEN 18 MINUTES, WHICH WOULD HAVE RESULTED IN TOTAL ENGINE FAILURE).