As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
*** DIVERSION *** SUPPLEMENTAL SDR *** AT FL 360 WE HAD A LEFT HYD DEM PUMP. WE NOTICED THE LEFT HYD QTY DROPPING RAPIDLY. EVENTUALLY THE LEFT HYD QTY EICAS CAME ON. WE TURNED OFF LEFT DEMAND PUMP WHICH SLOWED THE LOSS OF HYD FLUID R+R LEFT ENGINE ACMP PRESS. AND CASE DRAIN FILTER MODULE HYD LINE TO PRESSURE SWITCH PER AMM 20-11-00. LEAK CK GOOD. REPLACED PRESSURE SWITCH BLOCK PER AMM 29-11-18.