B767-3 FLT CREW HAS LOSS OF THE CTR HYD SYS DURING DSCNT INTO ORD.

Narrative

WHEN I ARRIVED BACK IN THE COCKPIT; THE FO'S BRIEFED ME THAT THE CTR HYD SYS QUANTITY HAD STARTED DROPPING SLOWLY JUST PRIOR TO THE TOP OF DSCNT. THEY HAD PERFORMED THE IRREGULAR OP FOR LOW HYD QUANTITY; AND HAD SHUT OFF THE CTR HYD PUMPS WITH THE QUANTITY AT .22. THEY HAD ALSO REVIEWED THE LOSS OF THE CTR HYD SYS IRREGULAR PROC. WE DISCUSSED A DIVERSION VERSUS CONTINUING TO ORD; AND DECIDED CONTINUING WOULD BE THE SAFEST COURSE OF ACTION BY GIVING US ENOUGH TIME TO THOROUGHLY TROUBLESHOOT AND BRIEF THE PROB. WE DISCUSSED ATTEMPTING TO LOWER THE LNDG GEAR WITH THE REMAINING FLUID; AND WHAT WOULD HAPPEN SHOULD THAT FAIL. WE THEN BRIEFED THE REMAINING ITEMS ON THE LOSS OF CTR SYS PROC; THE ALTERNATE GEAR EXTENSION AND THE ALTERNATE FLAP EXTENSION PROCS. FO; THE PF; AND AS I HAD JUST BEEN SOUND ASLEEP; I DECIDED THAT HAVING HIM CONTINUE TO FLY THE APCH AND LNDG WOULD PROBABLY BE THE SAFEST OPTION. AT THIS POINT; FO CONTACTED DISPATCH AND MAINT TO BRIEF THEM ON THE SITUATION; AND I BRIEFED THE FLT ATTENDANTS. I DID DECLARE A CABIN ADVISORY; AND TOLD THE FLT ATTENDANTS TO EXPECT A NORMAL LNDG WITH THE EXCEPTION THAT THE LNDG GEAR WOULD BE LOWERED EARLIER THAN USUAL AND THAT THE APCH SPD WOULD BE SLIGHTLY FASTER THAN NORMAL. I DECIDED THAT DECLARING AN EMER WITH ATC WAS NOT NECESSARY; BUT DID INFORM THEM OF THE SITUATION AND ASKED FOR A SLIGHTLY EXTENDED DOWNWIND/FINAL IN ORDER TO HAVE TIME TO ELECTRICALLY LOWER THE FLAPS. APPROX 20 MI FROM TOUCHDOWN WE ATTEMPTED TO LOWER THE GEAR NORMALLY. TURNING THE CTR SYS PUMPS ON RESULTED IN A CONTINUATION OF THE SLOW LEAK AND PUTTING THE GEAR HANDLE DOWN RESULTED IN THE EXTENSION OF ONLY THE NOSE GEAR. AT THIS POINT; WE SHUT THE CTR SYS OFF AND PERFORMED THE ALTERNATE GEAR EXTENSION PROC. SOME CTR SYS FLUID WAS REGAINED AFTER GEAR EXTENSION; BUT WE ELECTED TO EXTEND THE FLAPS WITH THE ALTERNATE SYS AND FINISHED THE ITEMS ON THE LOSS OF CTR SYS PROC. THE FLAP 20 DEG LNDG AND TAXI-IN WERE UNEVENTFUL.