Cessna 210 Centurion / Turbo Centurion 210C; 210D
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 35; Flight Crew Total 1750; Flight Crew Type 1400
Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Air Traffic Control Issued New Clearance; Flight Crew Diverted; Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Aircraft
While flying the initial part of the arrival in mild turbulence and IMC; my autopilot failed. The failure resulted in a full and hard left bank. The roll servo locked in a complete hard left bank and required pilot override. While struggling with controlling the aircraft and trying to prevent inversion; I had significant altitude and course deviations. Once I was able to diagnose the condition (locked roll servo) and pull the correct autopilot circuit breaker; I was able to regain proper control of the aircraft and shoot an RNAV approach to the closest airport. During this time; I informed Center; asked for a delay vector; and was given the same. ATC helped me identify the closest airport with a published approach.
C210 pilot reported a temporary loss of control due to the failure of the autopilot roll servo.