Date: 202201
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Haze / Smoke; 4
Light: Daylight
Aircraft: Citation II S2/Bravo (C550)
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class C ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Aileron Control System
Component problem: Malfunctioning
Reporter organization: Corporate
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Multiengine; Other SIC CE-550
Human factors: Troubleshooting; Situational Awareness; Communication Breakdown
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: We departed from Runway XXR. During climbout after flaps up; I noticed my Captain reach for the aileron trim and didn't think much of it. It wasn't until my Captain said that the aileron trim was stuck that I looked over and noticed he had a good input on the aileron to the right to fight the trim input that was on the left wing. Maintaining altitude and everything else wasn't an issue but it required excessive force from keeping the plane from turning.On the heading 213 off of the ZZZZZ3 departure we initially got 4;500 feet for traffic that was going to be above us. At that point we said that we would need to go back to ZZZ. We got asked if we needed assistance and I replied stand by. We took time to assess the situation and we said none as of now. We got transferred to a different Controller and then somewhere along the downwind (on a heading at that point) we decided to advise ATC since it was related to a flight control. I stated that we had 3.5 hours of fuel; 2 souls on board; and that it was due to a flight control issue. We got vectored for the ILS Z XXR and asked for delayed vectors several times so we could get ready and take our time. My Captain flew the whole time manually. We pulled up the no flap landing checklist to determine runway and speed. The concern we had was seeing how full flaps would effect stability. We decided to keep it at 7 degrees and plan for a REF of 120 and runway distance for Part 135 of 8;000 feet which was calculated from the checklist. We finished the appropriate checks and then came for a landing with a planned longer landing. No further assistance was required.In conclusion I'm glad we took our time and asked for delayed vectors. I definitely got reminded of the importance of flying the plane first and communicating second.


Second narrative: Started takeoff roll and rotated. After 400 feet; we raised the flaps and I noticed the airplane rolling to the left flying away from runway center line. I started to put right aileron to make the plane fly straight and noticed it was a considerable amount. We were on the ZZZZZ3 departure and started to turn right to our initial heading. The amount of force to turn was not normal and I tried to trim the ailerons and the aileron trim wheel was stuck. I told my copilot to tell ATC we need to head back to ZZZ. During the vectors for ILS XXR the yoke was turned to right with a good amount of force to fly straight. I decided to use flaps 7 and do a long landing. Throughout the whole approach; the yoke was about 30-45 degrees to the right to fly straight. We did not need any assistance.


Synopsis: C550 flight crew reported excessive control wheel input was required to stop the aircraft from rolling off course. Aileron trim was ineffective. The flight crew elected to return to the departure airport.