CE-550 flight crew reported that the aileron trim was mis-indexed after maintenance; resulting in partial loss of aircraft control that occurred right after takeoff. The flight crew performed an air turnback and safely landed.
Synopsis
CE-550 flight crew reported that the aileron trim was mis-indexed after maintenance; resulting in partial loss of aircraft control that occurred right after takeoff. The flight crew performed an air turnback and safely landed.
Narrative
Performed all preflight checklist and inspections of the aircraft to include the Before Taxi Checklist; Taxi Checklist; and Before Takeoff Checklist. Everything was operational including the flight control check. The CA was the PM and the First Officer was PF. Upon finishing the Before Takeoff Checklist; the CA transferred flight controls to the FO. Just after rotation; I noticed the aircraft yawed to the right and immediately looked at the turn coordinator to find the aircraft coordinated. PM called for positive rate and gear came up. 400 ft.; the flaps were raised to 0°. We were flying runway heading and assigned to fly 040° heading on departure. As soon as I started making my left turn to 040; I could tell the aircraft's flight controls were not normal. I was having to put excessive input to make my left turn. CA then told me I was banking 45° so corrected and that is when I felt like the aircraft was mis-trimmed. I called for autopilot to reduce workload and I remembered checking my PFD (Primary Flight Display) as well as the autopilot button. It felt like the autopilot did connect so I disengaged it with elevator trim on the yoke because we were reaching our assigned altitude of 3000 ft. and had not been cleared higher yet. I was still struggling to maintain directional control so I asked for the autopilot again and shortly after; the autopilot disconnect chimed again; but this time; the PFD said autopilot failure. CA asked for flight controls and I gave the controls to him; swapping PM and PF duties. We were cleared to 5000 ft.; but still struggling to maintain our assigned heading. We did have Aircraft Y traffic in the area above us. I made all the radio calls to Departure and asked to come back to ZZZ and requested vectors for the ILS. PF did not know if we were going to be able to maintain positive controls of the aircraft so we requested lower for the visual to Runway XX. We dropped down to 2500 ft. and popped out of the clouds and pointed the field out to the CA. We flew the visual in; ran the appropriate checklists; and landed the aircraft normally. It was a normal shutdown and the CA talked to passengers post shutdown. They seemed happy/relieved to be back and understood what was happening. CA explained that the aircraft was behaving in a way that he did not like. I opened the exit door for the passengers and they thanked me as well although they did seem a little shook up.
Second reporter narrative
Severe partial loss of control. Performed Before Taxi and Taxi Checklists in detail. Got released by ATC; performed Takeoff Checklist. First Officer was PF; Captain PM. Transferred controls to PF. Upon rotation; there was a noticeable yaw to the right. Positive rate; gear up. 400 ft.; flaps up; recce lights; synchronizer to FAN. At this moment; I saw PF PFD (Primary Flight Display) at 45 degrees of bank. I said Bank" and pointed. FO reacted to correct. He called for autopilot on and I engaged autopilot. A few seconds later; there was the autopilot disconnect chime and PF requested a second time autopilot on. I engaged autopilot and immediately noticed autopilot FAIL. PF was struggling to maintain directional control. I requested the aircraft and we exchanged controls. Somewhere before I took controls; I had contacted Departure and was radar contact. Was instructed to climb to 5000 and informed Aircraft Y was nearby. We were IMC at around 2200 ft. and therefore made no visual contact. I immediately recognized that plane was banking to the right and had to exert considerable force to keep wings level. I myself corrected the aircraft from going past 45-degree bank angle. Before reaching 5000; I requested return to ZZZ. ATC asked if they could be of assistance and I said no and wanted the ILS since we were IMC. At this time; things were happening very fast and we were still trying to figure out what was taking place. After what seemed to be 20 - 30 seconds of flying; I requested cancelling ILS and to have vectors for a visual. I was unsure if we could fly an entire ILS and wanted to get the aircraft to the ground as soon as possible. We were given vectors which I tried to follow. Recognizing that we were approaching ZZZ; I asked for 2500 hoping to pop out of IMC. It was granted. We popped in and out of clouds and FO found the airport; at which time I declared "Field in sight;" and flew a visual to the field. Landing was uneventful; smooth and centerline. We taxied back to FBO; shut down engines; and I informed passengers that the plane was not responding as I wanted and decided to return. Everyone on board said "Good choice" and "Thank you." FO opened door and as passengers left; they each said thank you again. They were very happy to be on the ground as it was probably not a very pleasant flight for them. For myself; there was a moment that I thought if this loss of control continued; we would not make it back."
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.