Caravan 208B
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 200; Flight Crew Total 1525; Flight Crew Type 1260
Human-Machine Interface; Time Pressure; Situational Awareness; Distraction; Communication Breakdown
Aircraft Equipment Problem Critical
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC Overrode Automation; Flight Crew Became Reoriented; Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action; General Maintenance Action
Aircraft
While shooting the ILS to 26R; I had an autopilot malfunction. This malfunction caused us to dramatically turn left and right and then oscillate up and down. I immediately disengaged the auto pilot and declared missed at that point so we could regain situational awareness. At that point; ATC asked the problem and we stated we were on the missed and would like to attempt the approach again. The second time was a success and I was given a phone number to call Tower when I shut down. I called the Tower and told them what happened and that I was calling my Maintenance Department to get the autopilot fixed. I wrote the autopilot up and it is scheduled to be repaired tomorrow.
A C-208B autopilot malfunctioned on a coupled ILS so the pilot disconnected it; executed a go around and returned to land. ATC inquired about the event and was told maintenance action would follow.