Date: 201207
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: Regional Jet 700 ER/LR (CRJ700)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Aileron Trim System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Other / Unknown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General Maintenance Action; General Work Refused
Contributing factors: Aircraft; Company Policy
Primary problem: Aircraft

Narrative: The Captain was the pilot flying and immediately upon rotation; there was a sudden drop of the right wing. So much so that I instinctively looked over to the oil pressure and other engine indications to make sure that our right engine did not fail. I then looked at the fuel balance to make sure that it was within limits. The left and right tanks were off by only 50 lbs. The PF had to input up to 50% left wing down trim for the aircraft to maintain wings level. Throughout the flight the same input was needed regardless of airspeed; altitude; power; and configuration. Upon landing at destination without incident; the Captain notified Maintenance Control of the excessive trim inputs required to hold the aircraft in a desirable state. The Maintenance Controller repeatedly told the Captain that the aircraft was fine and that the indications on the ED2 did not matter; 'that it was an instance of whatever it takes to get the job done' scenario as far as control surface trim was concerned. Neither the Captain; nor I felt comfortable with this information and cited our concerns in regards to possibilities of control loss in an engine failure; or PCU runaway event. The Maintenance Controller proceeded to read a service bulletin from Bombardier in regards to the aileron trim. The Captain then asked for a copy to be faxed so he and I could see this piece of paper. After that was done; we discovered that this bulletin also states that the max deviation was 31% for certification. Further; even to fly the aircraft to that extent required a ferry permit; and a concession from Bombardier. We did not have this concession from the manufacturer. The company also went on to say that the 31% certification limit was only for revenue flights. But nowhere did the Captain; nor I read that in the service bulletin. The sudden drop of the right wing on takeoff was caught instantly. I fear that if a situation arose where we needed full control authority of the left aileron; we would have been hampered by the abnormal amounts of trim (50% LWD) to maintain a wings level attitude.

Callback: The reporter states that no obvious faults were found by maintenance after the flight but that the company wanted the crew to ferry the aircraft to a Maintenance base which they declined. As of this time no cause for the anomaly has been determined.



Synopsis: CRJ700 First Officer experiences a sudden roll to the right as the Captain rotates the aircraft during takeoff. Once airborne it takes 50% LWD aileron trim to maintain the aircraft wings level at all speeds. The crew continues to destination landing uneventfully where post flight inspection by Maintenance reveals no obvious discrepancies in the ailerons or their trim tabs. The company requests that the crew ferry the aircraft which they decline.