Narrative:

While cruising we noticed a hydraulic low quantity for system 1 on EICAS. Checked mfd hydraulics page and system 1 was in amber range and falling. Called for QRH and advised company of situation. First officer ran QRH and notified company. We dropped the gear early since we were over weight for landing. Hydraulic quantity continued to fall. Engine one hydraulic fail EICAS message came on 10 minutes later and electric hydraulic pump automatically came on. Pressure in number one system was fluctuating for a second but maintained 2;900 psi. Company wanted the plane in [an en route airport] and we diverted. [We] notified flight attendant of situation. [We] made a normal landing. Declared emergency after an additional landing gear air ground fail EICAS message appeared 8 miles from the airport on final approach. Landing gear came down normally and breaking and steering were normal on landing.

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Original NASA ASRS Text

Title: EMB145 Captain experiences Hydraulic System 1 low quantity in cruise followed by a diversion to an airport suitable to the company.

Narrative: While cruising we noticed a Hydraulic Low Quantity for System 1 on EICAS. Checked MFD hydraulics page and System 1 was in amber range and falling. Called for QRH and advised company of situation. First Officer ran QRH and notified Company. We dropped the gear early since we were over weight for landing. Hydraulic quantity continued to fall. Engine One Hydraulic fail EICAS message came on 10 minutes later and electric hydraulic pump automatically came on. Pressure in number one system was fluctuating for a second but maintained 2;900 PSI. Company wanted the plane in [an en route airport] and we diverted. [We] notified flight attendant of situation. [We] made a normal landing. Declared emergency after an additional Landing Gear Air Ground fail EICAS message appeared 8 miles from the airport on final approach. Landing gear came down normally and breaking and steering were normal on landing.

Data retrieved from NASA's ASRS site as of July 2013 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.