As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER LEAVING RUNWAY ON TAKEOFF FROM GRAND CANYON, AZ, LEFT PROPELLER FEATHERED UNCOMMANDED BY CREW. FLIGHT ABORTED AND A SAFE LANDING WAS MADE AT VALLE AIRPORT, AZ. MAINTENANCE REPLACED DEFECTIVE TORQUE PRESSURE SWITCH ON RIGHT ENGINE.