As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE FL 350 HYD PRESS SENT TO ZERO AND HYD QTY WENT TO EMER/AUX POSITION. LOSS OF HYD QTY AND PRESS CHECKLIST ACCOMPLISHED. REPLACED PACKINGS & RETAINER RINGS REF IPC 29-11-24 ITEM 175,180,185 ON WING SLOT CONTROL VALVE IAW MM 27-80-04-2. LEAK AND OPS CHECKED GOOD. NO CONTROL VALVE ARM WAS DISCONNECTED OR ADJUSTED.