What was found
EN ROUTE, PILOT HAD A YELLOW HYD SYS LOW PRESSURE. SYS TURNED OFF REMAINDER OF FLIGHT. INVEST FOR HYD PUMP, FOUND PUMP OVERHEATED, INTERNAL PARTS DAMAGED. SKYDROL BURNED INSIDE PUMP, CREATING DEPOSITS. CLEANING IMPOSSIBLE. PUMP SWAPPED. ENG ANALYSIS OF FLUID REVEALED NO CHEMICAL CONTAMINATION.