Date: 201905
Local time of day: 0601-1200
Location: SCT.TRACON, CA
Flight conditions: IMC
Weather elements / visibility: Fog
Light: Daylight
Aircraft: PC-12
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Initial Approach
Airspace: Class C ZZZ
ATC / advisory: TRACON SCT
Aircraft component: GPS & Other Satellite Navigation
Component problem: Malfunctioning
Reporter organization: Corporate
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Instrument
Human factors: Human-Machine Interface; Situational Awareness; Troubleshooting; Distraction; Communication Breakdown
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Aircraft
Primary problem: Aircraft

Narrative: I filed an IFR flight plan for a flight to ZZZ. The aircraft I was flying was a Pilatus PC-12/45 equipped with Garmin G600's and GTN750's. The autopilot is a KFC 325 AP/FD. I departed and was radar vectored and climbed to 16;000 ft.; my requested altitude. During the climb I turned on the autopilot. The aircraft leveled off at 16;000 ft. and flew the route I had programmed into the GTN750 without issue. I picked up the ATIS for ZZZ. ZZZ was using the ILS so I set the ILS approach into the GTN750's and set the ILS front course into the G600. At that time; Center had me contact approach and the following events took place.I contacted and advised them I was at 16;000 ft. and I had the current ATIS. Approach told me to proceed direct to a fix and cross the fix at 8;000 ft. and 220 knots and to contact Approach. I checked on with the next sector and the controller assigned a heading of 270 and slow to 190 knots then descend to 5;000 ft. and to contact Approach. I checked on and I advised them I was descending to 5;000 ft. heading 270 and speed of 190 knots. The controller told me to turn right to a heading of 290 and that I was number 2 for the ILS. I set the heading to 290 and the aircraft turned to 290. The controller then told me to turn to a heading of 230 and descend to 3;000 ft. (I believe that is the heading and altitude assigned). I turned the heading knob to 230 and set 3;000 ft. I then noticed the aircraft was still on a 290 heading; but the heading bug was set to 230. The controller then told me they needed me to make the turn to 230. I replied to 'Stand by that I was having instrument trouble' the controller did not respond or acknowledge to me that I was having instrument trouble. At this point I checked the autopilot control head and verified the plane was in heading mode and that the autopilot was still engaged; it was. I next checked the G600 to make sure it was in heading mode; it was. I also checked to make sure it was not in GPS mode; it was not. While I was trouble shooting the issue; the controller told me to make the turn right now.At this point I determined one of the units was not working as it should and decided the best course of action was to use the emergency autopilot disconnect and hand fly the aircraft.After I disconnected the autopilot I told the controller I was turning to the assigned heading. The controller continued to give me vectors to the ILS. I intercepted the ILS and landed the aircraft. After landing; Ground control said I needed to call Approach for a possible pilot deviation. I called Approach and talked to the person who answered the phone; he asked me if I knew why they asked me to call. I stated Ground said I need to call about a possible loss of separation. He said they had a loss of separation between me and another aircraft. I stated that I reported to the controller I was having instrument trouble and that she never responded to me; his response was that she knew I was having instrument trouble.I feel that this loss of separation could have been avoided by simply working as a team. If the controller would have taken the time to ask what was going on or how she could help me; the loss of separation would have never happened. She could have given the other aircraft a short vector after I reported to her that I was having trouble. Instead she decided not to respond to me or take any action to assist me or ask me why I was not turning.




Synopsis: A Pilatus pilot reported being involved in a loss of separation when the auto pilot failed to fly the assigned heading.