Narrative:

On climb; a hydraulic system 1 low quantity advisory message was displayed. We followed the checklist in aom 1 and it directed us to monitor the quantity of the hydraulic fluid. When it was first detected; the quantity was right on the borderline between the green range and the amber range. There were no immediate indications of a leak or loss of hydraulic fluid because the fluid level remained steady and almost in the green range. After determining that we had a slow hydraulic leak; we decided that in the interest of safety it was prudent to divert to ZZZ. We notified dispatch and ATC and made plans for a precautionary landing. We reviewed the checklist for a hydraulic system 1 failure and prepared for that possibility; but the remaining fluid was sufficient to complete the flight without the loss of the system. We also informed the flight attendant; passenger and the local operations at ZZZ of the situation. After parking at the gate; maintenance confirmed that there was indeed a hydraulic leak and the aircraft was grounded. The hydraulic system 1 low quantity checklist directed us to monitor the hydraulic quantity. After a while; the quantity indicator moved very slowly from the top of the amber range to the middle of the amber range. At this time we were about 1 hour from our destination and only 15 mins from ZZZ.

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Original NASA ASRS Text

Title: AN EMB-135 FLT CREW RECEIVED A HYD SYS 1 LOW QTY MESSAGE. THEY MONITORED THE SITUATION AND DECIDED TO DIVERT TO A NEARBY AIRPORT.

Narrative: ON CLB; A HYD SYS 1 LOW QUANTITY ADVISORY MESSAGE WAS DISPLAYED. WE FOLLOWED THE CHKLIST IN AOM 1 AND IT DIRECTED US TO MONITOR THE QUANTITY OF THE HYD FLUID. WHEN IT WAS FIRST DETECTED; THE QUANTITY WAS RIGHT ON THE BORDERLINE BTWN THE GREEN RANGE AND THE AMBER RANGE. THERE WERE NO IMMEDIATE INDICATIONS OF A LEAK OR LOSS OF HYD FLUID BECAUSE THE FLUID LEVEL REMAINED STEADY AND ALMOST IN THE GREEN RANGE. AFTER DETERMINING THAT WE HAD A SLOW HYD LEAK; WE DECIDED THAT IN THE INTEREST OF SAFETY IT WAS PRUDENT TO DIVERT TO ZZZ. WE NOTIFIED DISPATCH AND ATC AND MADE PLANS FOR A PRECAUTIONARY LNDG. WE REVIEWED THE CHKLIST FOR A HYD SYS 1 FAILURE AND PREPARED FOR THAT POSSIBILITY; BUT THE REMAINING FLUID WAS SUFFICIENT TO COMPLETE THE FLT WITHOUT THE LOSS OF THE SYS. WE ALSO INFORMED THE FLT ATTENDANT; PAX AND THE LCL OPS AT ZZZ OF THE SITUATION. AFTER PARKING AT THE GATE; MAINT CONFIRMED THAT THERE WAS INDEED A HYD LEAK AND THE ACFT WAS GNDED. THE HYD SYS 1 LOW QUANTITY CHKLIST DIRECTED US TO MONITOR THE HYD QUANTITY. AFTER A WHILE; THE QUANTITY INDICATOR MOVED VERY SLOWLY FROM THE TOP OF THE AMBER RANGE TO THE MIDDLE OF THE AMBER RANGE. AT THIS TIME WE WERE ABOUT 1 HR FROM OUR DEST AND ONLY 15 MINS FROM ZZZ.

Data retrieved from NASA's ASRS site as of May 2009 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.