Narrative:

During cruise at FL370 we got the cyan 'hyd 2 qty low' massage. I pulled up the hydraulic page on the mfd and we were showing 0 quantity and 2;600 psi. All other indications were normal at that time. I monitored it for a few minutes and saw that the pressure in system 2 was dropping a few hundred psi then stabilizing and then dropping some more. I handed the aircraft over to my first officer and started looking at the hydraulic low press 1 (2) QRH in anticipation of the pressure fully dropping off. While doing that we got the edp 2 fail and hydraulic 2 low press amber massages almost simultaneously. The edp 2 fail was transient. I ran the hydraulic 2 low press QRH which called for turning on the electric hydraulic 2 pump. Once it was on the low press message extinguished and we were showing 16-1800 psi on the system. With the light out the checklist was complete. With 0 qty and only about 50 percent of normal pressure in the system I assumed it was not going to hold and started preparing to run the loss of hydraulic 2 QRH. I contacted dispatch and maintenance control and maintenance had me push the edp 2 shut off valve I assume just in case the leak was in the pump some fluid would be saved. But at 3;000 psi I would say the fluid was long gone. We looked at pit and cmh for a diversion and settled on cmh. We declared an emergency and had dispatch notify cmh that we would need to be towed to the gate. At that point I contacted the flight attendants on the interphone and notified them of the situation and that I was going to have them brief the passengers and that I would first speak with passengers about the situation. I had them brief the passengers and later notified the flight attendants that I was not going to have them brace; knowing since they were briefed I could always command a brace on the PA if there was a need later. I took the aircraft back on the decent around 3;000 feet and performed the landing. The landing was uneventful. The arff guys inspected the brakes and we shut down on the runway and were escorted in by airport ops under tow.

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Original NASA ASRS Text

Title: EMB175 flight crew experienced a Hydraulic 2 low quantity at FL370. After complying with QRH procedures the crew diverted to a suitable airport for an uneventful landing and tow to the gate.

Narrative: During Cruise at FL370 we got the cyan 'Hyd 2 Qty low' massage. I pulled up the Hydraulic page on the MFD and we were showing 0 quantity and 2;600 PSI. All other indications were normal at that time. I monitored it for a few minutes and saw that the pressure in system 2 was dropping a few hundred PSI then stabilizing and then dropping some more. I handed the aircraft over to my First Officer and started looking at the Hydraulic Low Press 1 (2) QRH in anticipation of the pressure fully dropping off. While doing that we got the EDP 2 Fail and Hydraulic 2 low press amber massages almost simultaneously. The EDP 2 Fail was transient. I ran the Hydraulic 2 Low press QRH which called for turning on the Electric Hydraulic 2 pump. Once it was on the Low Press message extinguished and we were showing 16-1800 PSI on the system. With the light out the checklist was complete. With 0 qty and only about 50 percent of normal pressure in the system I assumed it was not going to hold and started preparing to run the Loss of Hydraulic 2 QRH. I contacted Dispatch and Maintenance Control and Maintenance had me push the EDP 2 shut off valve I assume just in case the leak was in the pump some fluid would be saved. But at 3;000 PSI I would say the fluid was long gone. We looked at PIT and CMH for a diversion and settled on CMH. We declared an emergency and had Dispatch notify CMH that we would need to be towed to the gate. At that point I contacted the flight attendants on the interphone and notified them of the situation and that I was going to have them brief the passengers and that I would first speak with passengers about the situation. I had them brief the passengers and later notified the flight attendants that I was not going to have them brace; knowing since they were briefed I could always command a brace on the PA if there was a need later. I took the aircraft back on the decent around 3;000 feet and performed the landing. The landing was uneventful. The ARFF guys inspected the brakes and we shut down on the runway and were escorted in by airport ops under tow.

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.