RETURN LAND BY A B767-300 FLT CREW WHEN THE R HYD SYS DEVELOPS A FLUID LOSS OF UNKNOWN ORIGIN AFTER DEP LAX.

Narrative

DURING CLBOUT ON THE LAX 5 DEP; LAX -- UPON COMPLETION OF THE FL180 TKOF/CLB CHKLIST -- WE RECEIVED A R HYD QUANTITY EICAS MESSAGE. CAPT CALLED FOR QRH AND WE SELECTED STATUS PAGE TO NOTE A DECREASE (RAPID) IN R HYD QUANTITY. WE AGREED THAT THE RATE OF LOSS WOULD LEAD TO A TOTAL LOSS OF R HYD QUANTITY AND PROCEEDED WITH THE R HYD PRESSURE LOSS CHKLIST AND TURNED THE (BOTH) R HYD PUMPS OFF (STOPPING THE LOSS OF R HYD QUANTITY). WE CONTACTED MAINT AND OPS TO INFORM THEM OF OUR HYD SIT AND TO INFORM THEM OF OUR INTENTION TO RETURN TO LAX. WE ADDITIONALLY INFORMED ZLA OF OUR INTENTIONS/ACFT STATUS AND REQUESTED A RETURN TO LAX (DURING CHKLIST/TROUBLESHOOTING WE LEVELED AT FL290 AND SLOWED TO 300 KTS). WE WERE CLRED TO RETURN TO LAX VIA THE PDZ 4 ARR. WE DETERMINED THAT WE WERE INDEED UNDER THE MAX LNDG WT FOR THE ACFT AND CONTINUED TO AN UNEVENTFUL APCH AND LNDG. DURING PAX DEPLANING; A GENTLEMAN NOTED THAT DURING TAXI OUR (FLT CTL CHK); A SMALL 'BLAST' (SIC) OF WHAT APPEARED TO BE HYD FLUID; SPRAYED OUT FROM UNDER ONE OF THE R OUTBOARD SPOILERS. DURING THE POSTFLT WALKAROUND WE NOTED A PUDDLE OF HYD FLUID UNDER THE MID SECTION OF THE R WING. SUPPLEMENTAL INFO FROM ACN 623974: 1 HR 27 MINS LATER; WE RETURNED TO LAX; THE ACFT WENT OTS. WE BOARDED ANOTHER B767-300 AND DEPARTED.