As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CUSTOMER COMPLAINED THAT UPON PERFORMING REAR ENGINE MAGNETO CHECK, ONE MAGNETO PRODUCED NO DROP, THE OTHER MAGNETO WOULD CAUSE ENGINE DECELERATE TO THE POINT OF STOPPING. MAGNETO'S WERE REMOVED AND INSPECTED. FOUND IMPULSE COUPLING SPRING BROKEN. THIS IS THE THIRD SUCH SPRING FOUND BROKEN IN ONE MONTH.