Narrative:

I was first officer backup on jun/xx/97, from fra to ord. On arrival at the aircraft fra maintenance was working on the plane. The inbound crew reported a loss of fluid from the center hydraulic system. After working on the plane for over 2 hours, maintenance stated that they could not find the leak. It was decided to send out the flight and if there was no further problems after about 60 mins we could continue to ord. If there was a problem we could divert to lhr. Takeoff and climb out were uneventful. I went back for my break and in about 1 hour the first officer came back to keep me informed. He said that the right system was down to the refill mark and the center was down slightly also. He told me that the captain did not want to divert to lhr or even to call lhr maintenance for advice on the hydraulic system. We continued on but kept a constant watch on the hydraulic quantities. The quantities on the center and right system continued to decrease at a very slow rate. On coast-in the captain again decided not to contact dispatch either by HF or commercial radio. We did send several ACARS messages about our hydraulic quantity and asking dispatch to advise ord ATC that we wanted a long runway for landing. We discussed landing with the right and/or C hydraulic system out. We discussed turning off the right hydraulic pumps to save fluid but the captain decided to leave things as is. As we dropped gear and flaps the quantities decreased further but the landing was normal. After we got to the gate and after shutdown the right system went to zero. We found that a large spray of hydraulic fluid came from the right wheelwell. Supplemental information from acn 372107: first officer suggested problem with right system and questioned the center system write up in logbook. First officer suggested precautionary landing in london due to the potential problem involving center and right system and the availability of maintenance or spare airplane. Captain decided to continue to ord with alternates in mind. On arrival phase cockpit crew briefed abnormal approach and landing requesting long runway and speeds due to possible hydraulic failure. Normal approach/landing took place with near total loss of center and right system fluid on gear extension. Reserve brakes and steering was used on short final.

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Original NASA ASRS Text

Title: ACR MAINT PERSONNEL RELEASED A B767 FOR A TRANS-ATLANTIC FLT FROM A FOREIGN COUNTRY TO THE UNITED STATES OF AMERICA WITH A HYD PRESSURE LEAK NOTED IN THE ACFT LOGBOOK WHICH COULD NOT BE FOUND OR CORRECTED. THE FLC DEPARTED WITH ALTERNATE ARPTS PROPOSED IF MORE TROUBLE DEVELOPED. THE ACFT ARRIVED WITH A LOSS OF SYS FLUID IN ALL SYS, HARDLY ADEQUATE, FOR CTL OF THE ACFT FOR BOTH LNDG AND TAXIING TO THE GATE. CAPT VETOED FO REQUEST FOR PRECAUTIONARY LNDG.

Narrative: I WAS FO BACKUP ON JUN/XX/97, FROM FRA TO ORD. ON ARR AT THE ACFT FRA MAINT WAS WORKING ON THE PLANE. THE INBOUND CREW RPTED A LOSS OF FLUID FROM THE CTR HYD SYS. AFTER WORKING ON THE PLANE FOR OVER 2 HRS, MAINT STATED THAT THEY COULD NOT FIND THE LEAK. IT WAS DECIDED TO SEND OUT THE FLT AND IF THERE WAS NO FURTHER PROBS AFTER ABOUT 60 MINS WE COULD CONTINUE TO ORD. IF THERE WAS A PROB WE COULD DIVERT TO LHR. TKOF AND CLBOUT WERE UNEVENTFUL. I WENT BACK FOR MY BREAK AND IN ABOUT 1 HR THE FO CAME BACK TO KEEP ME INFORMED. HE SAID THAT THE R SYS WAS DOWN TO THE REFILL MARK AND THE CTR WAS DOWN SLIGHTLY ALSO. HE TOLD ME THAT THE CAPT DID NOT WANT TO DIVERT TO LHR OR EVEN TO CALL LHR MAINT FOR ADVICE ON THE HYD SYS. WE CONTINUED ON BUT KEPT A CONSTANT WATCH ON THE HYD QUANTITIES. THE QUANTITIES ON THE CTR AND R SYS CONTINUED TO DECREASE AT A VERY SLOW RATE. ON COAST-IN THE CAPT AGAIN DECIDED NOT TO CONTACT DISPATCH EITHER BY HF OR COMMERCIAL RADIO. WE DID SEND SEVERAL ACARS MESSAGES ABOUT OUR HYD QUANTITY AND ASKING DISPATCH TO ADVISE ORD ATC THAT WE WANTED A LONG RWY FOR LNDG. WE DISCUSSED LNDG WITH THE R AND/OR C HYD SYS OUT. WE DISCUSSED TURNING OFF THE R HYD PUMPS TO SAVE FLUID BUT THE CAPT DECIDED TO LEAVE THINGS AS IS. AS WE DROPPED GEAR AND FLAPS THE QUANTITIES DECREASED FURTHER BUT THE LNDG WAS NORMAL. AFTER WE GOT TO THE GATE AND AFTER SHUTDOWN THE R SYS WENT TO ZERO. WE FOUND THAT A LARGE SPRAY OF HYD FLUID CAME FROM THE R WHEELWELL. SUPPLEMENTAL INFO FROM ACN 372107: FO SUGGESTED PROB WITH R SYS AND QUESTIONED THE CTR SYS WRITE UP IN LOGBOOK. FO SUGGESTED PRECAUTIONARY LNDG IN LONDON DUE TO THE POTENTIAL PROB INVOLVING CTR AND R SYS AND THE AVAILABILITY OF MAINT OR SPARE AIRPLANE. CAPT DECIDED TO CONTINUE TO ORD WITH ALTERNATES IN MIND. ON ARR PHASE COCKPIT CREW BRIEFED ABNORMAL APCH AND LNDG REQUESTING LONG RWY AND SPDS DUE TO POSSIBLE HYD FAILURE. NORMAL APCH/LNDG TOOK PLACE WITH NEAR TOTAL LOSS OF CTR AND R SYS FLUID ON GEAR EXTENSION. RESERVE BRAKES AND STEERING WAS USED ON SHORT FINAL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.