Narrative:

During single pilot operations climb out in IMC; turbulence and light icing at approximately through 14000 ft the autopilot began to not track course headings and while I was troubleshooting systems and confirming ice protection and airframe configuration the autopilot disengaged completely. The plane began a sharp turn to the left and the yoke required 10 to 15 lbs of force to hold the plane in straight and level flight; and I eventually continued to climb. Broke out of cloud tops at approx 240 and could see build ups higher ahead. Continued in and out of IMC while trying to avoid bigger build-ups and did request heading variations from ATC. Cleared to and reached FL270 and was just in the tops of clouds hand flying the plane. The plane had recently been repaired from aileron damage incurred in the hangar last month. The damaged aileron was ultimately replaced with new component and several test flights were completed and missions had been flown at low altitudes (below 10000 ft). In those tests the plane was flying slight heavy to the left but very manageable. Hands-off trimmed straight and level was possible before the plane started drifting left; which a little rudder could help with. And autopilot operations were confirmed. It was thought that some trim tab adjustments could be done over the course of the next few missions to get the airframe trimmed for no-input level flight. During this incident the plane required significant pressure on the yolk to maintain level flight as the plane operated above 14000 ft. The autopilot could not hold the course heading for more than a few minutes. This new control surface and the related changes to the rigging obviously behaved much different at higher altitudes than in the test flights at 3000-5000 MSL. In addition to the wide variations in headings induced by the avoidance of build-ups and the difficulty hand-flying the airplane in IMC with such heavy flight control pressures required; I did drift above the assigned altitude of 270 by 300-500 ft at times. FL270 was right at the tops and my unconscious desire to stay VMC on top and out of potential icing at the cloud tops had me fighting the visual reference to fly just above the layer. I eventually did request and was granted clearance to FL280 which kept me comfortably above the tops until past the front in another 75nm. The forecast and indicated weather was VMC the balance of the trip so I decided to hand fly the airplane to my intended home field destination. I was able to re-engage the autopilot for 10-15 minute periods which provided some relief.

Related reports:

Google
 

Original NASA ASRS Text

Title: A PA46 aileron was replaced and low altitude test flights resolved aileron trim issues causing drift. At FL270 the trim required was considerably different and the pilot had difficulty controlling the aircraft.

Narrative: During single pilot operations climb out in IMC; turbulence and light icing at approximately through 14000 ft the autopilot began to not track course headings and while I was troubleshooting systems and confirming ice protection and airframe configuration the autopilot disengaged completely. The plane began a sharp turn to the left and the yoke required 10 to 15 lbs of force to hold the plane in straight and level flight; and I eventually continued to climb. Broke out of cloud tops at approx 240 and could see build ups higher ahead. Continued in and out of IMC while trying to avoid bigger build-ups and did request heading variations from ATC. Cleared to and reached FL270 and was just in the tops of clouds hand flying the plane. The plane had recently been repaired from aileron damage incurred in the hangar last month. The damaged aileron was ultimately replaced with new component and several test flights were completed and missions had been flown at low altitudes (below 10000 ft). In those tests the plane was flying slight heavy to the left but very manageable. Hands-off trimmed straight and level was possible before the plane started drifting left; which a little rudder could help with. And autopilot operations were confirmed. It was thought that some trim tab adjustments could be done over the course of the next few missions to get the airframe trimmed for no-input level flight. During this incident the plane required significant pressure on the yolk to maintain level flight as the plane operated above 14000 ft. The autopilot could not hold the course heading for more than a few minutes. This new control surface and the related changes to the rigging obviously behaved much different at higher altitudes than in the test flights at 3000-5000 MSL. In addition to the wide variations in headings induced by the avoidance of build-ups and the difficulty hand-flying the airplane in IMC with such heavy flight control pressures required; I did drift above the assigned altitude of 270 by 300-500 ft at times. FL270 was right at the tops and my unconscious desire to stay VMC on top and out of potential icing at the cloud tops had me fighting the visual reference to fly just above the layer. I eventually did request and was granted clearance to FL280 which kept me comfortably above the tops until past the front in another 75nm. The forecast and indicated weather was VMC the balance of the trip so I decided to hand fly the airplane to my intended home field destination. I was able to re-engage the autopilot for 10-15 minute periods which provided some relief.

Data retrieved from NASA's ASRS site as of April 2012 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.