What was found
ENGINE/TRANSMISSION COUPLING, VIBRATION OF ACTUATOR CAUSED ACTUATOR SPRINGS TO VIBRATE ON BOTH SWITCHES AND, THEREFORE, ONE BELT TENSION SWITCH TO BREAK. SWITCH BROKE IN CLOSED POSITION. SPRINGS TOO WEAK TO WITHSTAND VIBRATION.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
ENGINE/TRANSMISSION COUPLING, VIBRATION OF ACTUATOR CAUSED ACTUATOR SPRINGS TO VIBRATE ON BOTH SWITCHES AND, THEREFORE, ONE BELT TENSION SWITCH TO BREAK. SWITCH BROKE IN CLOSED POSITION. SPRINGS TOO WEAK TO WITHSTAND VIBRATION.