As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT, HYD SYS FAILURE DUE TO DAMAGED SPLINES ON HYD PUMP, PN-704A34310006 AND DRIVE COUPLING, PN-704A33635002. SPLINES FOUND TO BE SEVERLY WORN AND UNABLE TO ENGAGE FOR PUMP OPERATION. UNSURE OF REASONING FOR SPLINE FAILURE AT THIS POINT.