Narrative:

During flight an EICAS left hydraulic qty came on with the associated lights on the overhead; and the status page showed RF 0.43. The first officer was in the restroom. When he came back in we ran the left hydraulic qty checklist. After that we had 2 new messages; left hydraulic pressure and the rudder ratio EICAS and associated overhead lights. We contacted dispatch and maintenance. We decided because we only had a single failure to continue; but declare an emergency and have the equipment standing by as a precaution. We advised the purser of the cabin advisory and asked him if he had any questions or concerns. We looked up the landing data and due to the 15 KT crosswind on the runway in use (max allowable because of rudder ration light) elected to land with a direct headwind on a different runway. We configured methodically and slowly and landed without incident. The left hydraulic quantity indicated 0.17 to 0.25; the standpipe amount. Made a PA to the passengers. Dispatcher was great; professional; and helpful. ATC was great as well. We taxied into the pad and shutdown the engines; I turned off all the hydraulic pumps on the left side and left the flaps at 30 because I did not want to burn up the pump or create any other damage. We were towed to the gate.

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Original NASA ASRS Text

Title: B757-200 flight crew experiences a left hydraulic system low quantity EICAS message at FL370 and elects to continue to destination after turning of the left hydraulic system pumps. The pumps are turned on for landing allowing normal flap and gear extension. Aircraft is towed to the gate after landing due to continued fluid loss.

Narrative: During flight an EICAS L HYD QTY came on with the associated lights on the overhead; and the status page showed RF 0.43. The First Officer was in the restroom. When he came back in we ran the L HYD QTY checklist. After that we had 2 new messages; L HYD PRESSURE and the RUDDER RATIO EICAS and associated overhead lights. We contacted Dispatch and Maintenance. We decided because we only had a single failure to continue; but declare an emergency and have the equipment standing by as a precaution. We advised the Purser of the cabin advisory and asked him if he had any questions or concerns. We looked up the landing data and due to the 15 KT crosswind on the runway in use (max allowable because of rudder ration light) elected to land with a direct headwind on a different runway. We configured methodically and slowly and landed without incident. The left hydraulic quantity indicated 0.17 to 0.25; the standpipe amount. Made a PA to the passengers. Dispatcher was great; professional; and helpful. ATC was great as well. We taxied into the pad and shutdown the engines; I turned off all the hydraulic pumps on the left side and left the flaps at 30 because I did not want to burn up the pump or create any other damage. We were towed to the gate.

Data retrieved from NASA's ASRS site as of April 2012 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.