Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 30
Situational Awareness
Aircraft Equipment Problem Less Severe
Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft
We were flying to ZZZZ and were at cruise altitude about half way through the flight. I happened to look at the status page and noticed our center hydraulic quantity was indicating .54 RF and decreasing. We had no EICAS messages at that point but we started to review the QRH procedures and made a call to [Operations] and Maintenance to get them in the loop. Soon thereafter; we got the HYD QUANT EICAS message and observed that the center tank quantity was still decreasing at a steady rate. There were no actions to complete at that point. We figured that the C Hadraulic System Pressure message was not far behind. After reviewing QRH procedure and the Non Normal Configuration Landing Distances chart; we all agreed that ZZZZ had plenty of runway length and it was safe to continue there and land at flaps 20. We also noted from the C Hydraulic System Pressure QRH Procedure that we MAY not have nose wheel steering after landing dependent on where the leak was located in relation to the center tank standpipe for reserve brakes and steering. Based on that; we also agreed that it would be prudent to declare an emergency and have a tug standing by to help us vacate the runway IF needed. [Maintenance Control] did a great job coordinating because everyone seemed to know our situation ahead of time. However; the First Officer and I agreed to hold off [drastic measures] until we actually got the C system pressure message that would actually drive the QRH procedure that we had been reviewing. The center quantity had dropped to .15 and seemed to stabilize and we still no system pressure message. We assumed we would get it when we started flap extension so we configured early to give us time to run the checklist. We extended the flaps to 20 hydraulically and still had no message. It wasn't until after we lowered the gear that we finally got the C System Pressure EICAS message. At that point; we ran the checklist and then declared an emergency. We landed flaps 20 and had full nose wheel steering capability via the reserve brakes and steering system. We were able to vacate the runway and taxi to the ramp under our own power with no other incidents.
[Report narrative contained no additional information.]
The B767 lost the C Hydraulic System and landed at its destination uneventfully.