What was found
(CAN) RECEIVED A REPORT FROM A PRIVATE OPERATOR THAT AN ACFT HAD AN UNCOMMANDED REVERSION TO MANUAL MODE FOLLOWED BY AN ENGINE OVERSPEED. FOLLOWING A DOWNLOAD OF THE ECU INCIDENT RECORDER IT WAS NOTED THAT THE REVERSIONARY GOVERNOR HAD FAILED AND WITHIN 5 SECONDS AFTERWARDS THE PRIMARY CHANNEL FAILED AS WELL REVERTING THE ACFT INTO THE MANUAL MODE AND CAUSING AN ENGINE NP OVERSPEED UP TO 118.1 PERCENT.