As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH AIRCRAFT ON THE GROUND AND ALL THREE GEARS DOWN AND LOCKED, HYDRAULIC POWER WAS PUT ONTO THE AIRCRAFT. AT THAT POINT, THE NOSE GEAR RETRACTED UP DROPPING THE NOSE TO THE GROUND. INSPECTION OF THE CONTROL SYSTEM FOR THE LANDING GEAR WAS FOUND OK. WHAT WAS FOUND WAS THE SPOOL VALVE FOR THE LANDING GEAR WAS STUCK IN THE GEAR UP POSITION.