As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE HAD UNCONTROLLED ACCELERATION FROM IDLE. RPM OF NF REACHED 110% BEFORE MANUAL GOVERNOR WAS ENGAGED AND ENGINE SECURED. INVESTIGATION REVEALED NO LOOSE LINES, NO LINES WITH ICE, AND AFCU DRIVESHAFT WAS SERVICABLE. ENGINE WAS REMOVED AND RETURNED TO PRATT & WHITNEY FOR EVALUATION AND REPAIR.