Cessna 210 Centurion / Turbo Centurion 210C; 210D
Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 25; Flight Crew Total 5850; Flight Crew Type 600
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude
Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action
Aircraft
Vectors in IFR conditions at 5;000 feet. Autopilot electric trim went full down. Could not disconnect on yoke switch also Manual switch on auto pilot would not disengage so I pulled circuit breaker but had lost 600 feet. I reset circuit breaker and everything worked as usual
Cessna 210 pilot reported the electric trim moved full down and could not be disconnected by using the yoke switch. Reporter stated they reset the circuit breaker and the trim then functioned normally.