What was found
AIR TURN BACK-LOSS OF HYDRUALIC QUANTITY HYD QTY READS ZERO HYD QTY LGT ILLUM, EICAS MSG DISPLAYED L HYD QTY HYDRAULIC LOW PRESS ON. FOUND BROKEN PACKING ON RT ELEV PCU LEFT SYS. REPLACED PACKING LEAK CK'D RAN LEFT ENG CYCLED FLIGHT CONTROLS ALL SYSTEM'S CK NORMAL, OKAY FOR SERVICE.