As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AIRCRAFT STARTED UNCOMMANDED DESCENT WITH NOSE PITCH UP. ROTOR SPLIT HIGH TO 107. ESTABLISHED CONTROL. FOUND COLLECTIVE WANTED TO DRIVE FULL DOWN. DISENGAGED COLLECTIVE TRIM AND PROBLEM CEASED. SWAPPED FROM FD NR 1 TO FD NR 2 AND PROBLEM CEASED THEN TRIED FD NR 1 AGAIN WITHOUT PROBLEM. RETURNED TO HOUMA AND DURING GROUND TEST, WITH APU ON, COLLECTIVE WOULD DRIVE DOWN.