As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS ON DESCENT INTO MSP, AFTER REDUCING POWER THE ENGINE KEPT SPOOLING DOWN AT THAT POINT THE PILOTS SHUT THE ENGINE DOWN. ACFT LANDED WITH NO FURTHER PROBLEMS. INVESTIGATION REVEALED THE HMU LEVER NUT HAD LOOSENED UP ENOUGH TO ALLOW THE LEVER TO SLIP OUT OF THE RIG AND ALLOW THE ENGINE TO SHUT DOWN.