Narrative:

In cruise flight we got a master caution and hydraulic look down light. We identified the problem and the main accumulator pressure was low; the quantity was ok; and the emergency/inboard/outboard accumulator pressures were ok. We began running the QRH and did an emergency gear extension while we knew we had hydraulic pressure. About that time; we were handed off to approach. We got the weather and found out the winds were 270/9; 6 miles visibility; and broken at 900. The ILS and localizer approach to 22 was OTS and they were using a GPS approach. We checked the weather at a nearby airport since we had just passed by and found winds 320/8; 3 miles visibility; and broken at 1;700. We decided it would be best to divert there due to the much more favorable weather and the fact that we did not know how well the brakes would work. We were unable to get a hold of dispatch because we were too low. We declared an emergency and began diverting. We finished running the QRH; informed the divert airport operations; and had them notify dispatch. We shot the localizer back course course. We stopped on the runway. We had already notified operations that we would need to be towed in. We kept the passengers on board; put in the gear pins; and got towed into the gate where we deplaned.

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Original NASA ASRS Text

Title: A SF340 hydraulic system failed in flight but the accumulators retained pressure so the landing gear was lowered; an emergency declared and the flight diverted to a nearby airport with weather more favorable than the planned destination.

Narrative: In cruise flight we got a Master Caution and hydraulic look down light. We identified the problem and the main accumulator pressure was low; the quantity was OK; and the emergency/inboard/outboard accumulator pressures were OK. We began running the QRH and did an emergency gear extension while we knew we had hydraulic pressure. About that time; we were handed off to Approach. We got the weather and found out the winds were 270/9; 6 miles visibility; and broken at 900. The ILS and LOC approach to 22 was OTS and they were using a GPS approach. We checked the weather at a nearby airport since we had just passed by and found winds 320/8; 3 miles visibility; and broken at 1;700. We decided it would be best to divert there due to the much more favorable weather and the fact that we did not know how well the brakes would work. We were unable to get a hold of Dispatch because we were too low. We declared an emergency and began diverting. We finished running the QRH; informed the divert airport Operations; and had them notify Dispatch. We shot the LOC BC course. We stopped on the runway. We had already notified Operations that we would need to be towed in. We kept the passengers on board; put in the gear pins; and got towed into the gate where we deplaned.

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.