What was found
PDIS 390 29-02 9785 03DEC19 DEN FACT U LOGPAGES:3149673 AT FL 340, RECEIVED LEVEL 1 "HYD 3 ELEV OFF". SWITCHED FROM AUTOPILOT 2 TO AUTOPILOT 1. RECEIVED SUBSEQUENT "HYD 3 QTY LO", ACCOMPANIED BY " HYD 3 FAIL". FACT 03DEC19 04:39 DEN U SERVICED #1 AND #3 HYD SYSTEMS REF AMM 12-13-02-3. BLED AIR FROM ALL HYDRAULIC SYSTEMS REF AMM 29-03-00-2. RAN ELEC AND ENGINE HYD PUMPS AND FOUND NO LEAKS. CHECKED TAIL CONE, AFT ACCESSORY COMPT, STAB COMP, CAC, CENTER WHEEL WELL AND BOTH MAIN WHEEL WELLS WITH NO LEAKS NOTED. RAN ALL FLIGHT CONTROLS WITH ELEC AND ENG PUMPS, NO LEAKS NOTED. EXERCISED NOSE WHEEL STEERING, NO LEAKS. RAN ALL 3 ENGINES REF JRH FOR 30 MINS WHILE MOVING FLIGHT CONTROLS. NO LEAKS NOTED. NO DROP IN HYDRAULIC QTY DURING APPROX 3 HOURS OF T/S. A/C OK FOR SERVICE