Flight Crew Commercial
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem
Aircraft
On descent into CMH; autopilot trim warning illuminated on CAWS panel followed by the audible tone indication for a runaway autopilot trim. The pilot flying felt pressure on the control yoke indicating control pressure not being free from the control servo manipulated by the autopilot. He then disconnected the autopilot using CWS and the pitch trim trigger on the control yoke. The audible tone sounded when the autopilot disconnected. The autopilot annunciator light extinguished on the autopilot mode panel and the autopilot CAWS (caution) did not illuminate. The pilot flying did not feel the control pressure pitching the aircraft down relieve with the autopilot turned off. The pilot flying ordered and I executed the trim interrupt procedure in the QRH. Upon completion of the QRH procedure for pitch trim runaway; pitch trim was adjusted using primary stab trim. No additional system faults were experienced.
A PC-12 flight crew received a runaway autopilot stabilizer trim warning; followed the QRH procedure and completed the flight successfully.