Narrative:

While taxiing to runway 12L we got a fuel imbal caution message (fuel imbal of 800 pounds or more). We requested to pull off onto the deicing pad and run the QRH on fuel imbal. We waited on the pad for about 10 mins while we manually xferred fuel until the message was out and then some. I think it was 725 imbal, which is within limits. We took off on runway 12L and on the climb out got the fuel imbal caution message again. We again ran the QRH but were unable to bring the imbal within limits. We called ZZZ and requested a return to ZZZ for a precautionary landing. We did not declare an emergency, but ZZZ rolled crash fire rescue equipment on our behalf. As we were making our approach into ZZZ on the ILS runway 12L, the fuel imbal went below 800 pounds difference and the caution message went out. We landed safely on runway 12L and taxied to the gate, where we changed aircraft and made the trip successfully. My thoughts: I'm not sure, but I think the captain may have missed the gravity xflow valve on his cleared-to-start check. Leaving the valve open would cause fuel to xfer from the left and right tanks freely when the aircraft is being taxied. When we got our first caution message on the ground, I looked over at the message on ED1, but out of the corner of my eye I saw the captain reach for something on the overhead panel. I think he may have closed the valve at that time. Also, the QRH is intended for xferring fuel while airborne. There is no corrective action that I know of for a fuel imbal on the ground. I also missed the 3 notes (in small print) on the QRH. One of them said to level the aircraft for 30 seconds while xferring fuel manually. We never did that. In the heat of the moment, I missed it and didn't read it to the captain. The print and flow of the QRH could use some improvements.

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Original NASA ASRS Text

Title: A CL600 CREW RECEIVED A FUEL IMBAL CAUTION PRIOR TO TKOF, ADJUSTED THE FUEL AND DEPARTED. AFTER TKOF, THE IMBAL OCCURRED AGAIN. THE CREW RETURNED TO THE DEP ARPT.

Narrative: WHILE TAXIING TO RWY 12L WE GOT A FUEL IMBAL CAUTION MESSAGE (FUEL IMBAL OF 800 LBS OR MORE). WE REQUESTED TO PULL OFF ONTO THE DEICING PAD AND RUN THE QRH ON FUEL IMBAL. WE WAITED ON THE PAD FOR ABOUT 10 MINS WHILE WE MANUALLY XFERRED FUEL UNTIL THE MESSAGE WAS OUT AND THEN SOME. I THINK IT WAS 725 IMBAL, WHICH IS WITHIN LIMITS. WE TOOK OFF ON RWY 12L AND ON THE CLBOUT GOT THE FUEL IMBAL CAUTION MESSAGE AGAIN. WE AGAIN RAN THE QRH BUT WERE UNABLE TO BRING THE IMBAL WITHIN LIMITS. WE CALLED ZZZ AND REQUESTED A RETURN TO ZZZ FOR A PRECAUTIONARY LNDG. WE DID NOT DECLARE AN EMER, BUT ZZZ ROLLED CFR ON OUR BEHALF. AS WE WERE MAKING OUR APCH INTO ZZZ ON THE ILS RWY 12L, THE FUEL IMBAL WENT BELOW 800 LBS DIFFERENCE AND THE CAUTION MESSAGE WENT OUT. WE LANDED SAFELY ON RWY 12L AND TAXIED TO THE GATE, WHERE WE CHANGED ACFT AND MADE THE TRIP SUCCESSFULLY. MY THOUGHTS: I'M NOT SURE, BUT I THINK THE CAPT MAY HAVE MISSED THE GRAVITY XFLOW VALVE ON HIS CLRED-TO-START CHK. LEAVING THE VALVE OPEN WOULD CAUSE FUEL TO XFER FROM THE L AND R TANKS FREELY WHEN THE ACFT IS BEING TAXIED. WHEN WE GOT OUR FIRST CAUTION MESSAGE ON THE GND, I LOOKED OVER AT THE MESSAGE ON ED1, BUT OUT OF THE CORNER OF MY EYE I SAW THE CAPT REACH FOR SOMETHING ON THE OVERHEAD PANEL. I THINK HE MAY HAVE CLOSED THE VALVE AT THAT TIME. ALSO, THE QRH IS INTENDED FOR XFERRING FUEL WHILE AIRBORNE. THERE IS NO CORRECTIVE ACTION THAT I KNOW OF FOR A FUEL IMBAL ON THE GND. I ALSO MISSED THE 3 NOTES (IN SMALL PRINT) ON THE QRH. ONE OF THEM SAID TO LEVEL THE ACFT FOR 30 SECONDS WHILE XFERRING FUEL MANUALLY. WE NEVER DID THAT. IN THE HEAT OF THE MOMENT, I MISSED IT AND DIDN'T READ IT TO THE CAPT. THE PRINT AND FLOW OF THE QRH COULD USE SOME IMPROVEMENTS.

Data retrieved from NASA's ASRS site as of July 2007 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.