What was found
(CAN) 1 HYD" CAUTION ILLUMINATED IN FLIGHT CLOSELY FOLLOWED BY NR 1 HYD ISO, CAUTION LIGHT. NR 1 HYDRAULIC QUALITY QUICKLY DROPPED TO 0. TECH CREW CARRIED OUT AN AIR RETURN AND DECLARED A, PAN. TOTAL FLIGHT TIME RECORDED WAS 1 HR, WITH THE NR 1 SYS BEING REPORTED SHOWING ZERO QTY FOR APPROXIMATELY 40 MINUTES OF THIS TIME. THE ENGINEER FOUND AND CONFIRMED THE LT OTBD ELEVATOR PCU HOSE ASSY PN AS-116-04-0133 HAD RUPTURED, REF AIPC29-10-00, FIG 50, ITEM 600. CAUSING THE SYSTEM FLUID LOSS.