Date: 201811
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Turbulence
Light: Night
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Airspace: Class B ZZZ
Aircraft component: Fuel Distribution System
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Distraction; Confusion
Anomaly: Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew; Person Ground Personnel
When detected: In-flight; Aircraft In Service At Gate
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Human Factors; Company Policy
Primary problem: Ambiguous

Narrative: We were parked in ZZZ preparing for flight to ZZZ1. A ramper came into the cabin and asked the Captain to come outside because the fueler spilled some fuel out of the left wing. Captain went outside to assess the situation. He came back to the cockpit and advised me it was quite a bit of fuel and they were getting the spill kit to clean it up. Eventually the mess was cleaned up; during which time Maintenance came into the airplane and to check the fuel quantity; and verified that matched the amount that was said to be onboard on the fueling panel. We had the required amount of 17.3 fuel required for dispatch so they agreed that we were ok to operate the flight. Maintenance suggested that maybe the pressure fuel was too great for the aircraft causing it to spill out the overflow pressure release valve out of the wing. It sounded logical and we continued with our duties. Shortly after a Port Authority officer came into the plane and asked if we were good to operate the flight and if everything was ok. Captain advised him yes and we were going to ZZZ1.Taxi and takeoff were normal. As we were climbing out (I was hand flying) we were given a left turn and as I initiated the turn I noticed the plane was not turning smoothly and didn't want to turn left. There was a pretty strong wind from the west and I thought it was probably due to the weather (cloud layer and winds). We got a FUEL IMBALANCE caution message during the turn for about 5 seconds. Captain reached for the QRH and by the time he was searching for the page the message extinguished. He then pulled up the fuel page and we noticed the left pumping fuel to the right. We both agreed it was a little odd. Then we checked the fuel quantity and it showed we had burned less than 500lbs. We thought maybe it was showing slightly erroneous because we were still climbing. Our first level off was assigned at 11000 feet. We agreed to give it a couple minutes to correct itself as the plane sometimes needs. We leveled at 11000 feet and as the nose came down the fuel quantity increased. We were now showing that we had started engines; taxied; taken off; and climbed to 11000 feet all while burning less than 500lbs of fuel as we were still indicating 16800lbs. We both agreed that was impossible! A message was sent to dispatch to try to verify the amount of fuel that was taken off the truck and put into the plane. While we were waiting for a response we continued to investigate the fuel page and concluded from amount used and amount remaining that we must have had about 18300lbs. A short while later; dispatch came back to us saying that we landed from our previous flight with 6900lbs. The fuel truck put on 1700 gallons (1700 gallons X 6.7lbs/gal = 11390lbs) (11390lbs + 6900lbs = 18290lbs). That confirmed our estimation of having 18300lbs; or being 1000lbs over what we were supposed to be. To make the matter even worse that 1000lbs was not equally balanced throughout the airplane as we had more in the left wing than anywhere else.As the flight continued; fuel calculations were done and we were burning at a normal rate. Our estimate of 18300 lbs was holding steady and the decision to continue the flight to the destination was made. The flight continued without incident and landed safely.This is my first time having an 'undesired aircraft state' during my employment here. We were extremely lucky that we only had [a few dozen] passengers on board as this could have very easily turned into an overweight departure.Furthermore; performance is based on weight; while we all know a 'fudge factor' is built into the numbers 1000lbs would exceed that factor by anyone's opinion. Safety is the number one priority of everyone at this airline. Quality maintenance and proper planning and execution contribute to safety; but this error needs to be fixed to ensure something like this never happens again. Next time the airplane might be full and we might not be as lucky.




Synopsis: CRJ-900 First Officer reported that the aircraft was found to have been fueled improperly; causing a weight and balance asymmetry in flight.