Date: 201910
Local time of day: 0001-0600
Location: ZAU.ARTCC, IL
Flight conditions: Mixed
Weather elements / visibility: Rain; 10
Light: Night
Aircraft: Golden Eagle 421
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Descent
Airspace: Class E ZAU
ATC / advisory: Center ZAU
Second aircraft: PA-31 Navajo/Chieftan/Mojave/T1040
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Situational Awareness
Second reporter function: Single Pilot; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic; Aircraft Equipment Problem Dissipated; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; Flight Crew Regained Aircraft Control; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: I just took over the sector. Aircraft X had a crossing of a fix at 4;000 feet. Aircraft Y was at 7;000 feet; with a vector behind Aircraft X. Aircraft X was through I believe 6;800 feet; so I knew I could get Aircraft Y on course soon. I gave a couple of clearances to other aircraft; and was evaluating a situation to the north when I saw Aircraft X climbing and flying roughly a 070 heading (mind you his flight plan and previous path was approximately a 280 heading.) I immediately asked what his altitude was; and expedited him down; calling the traffic. I then called traffic for Aircraft Y. I informed Aircraft X that he was flying away from his assigned flight plan. He said that he 'lost power to the panel; and was correcting.' I asked if everything was ok; and he said he had everything back. I gave a few other clearances; made sure Aircraft X was ok; then advised he calls Center because of a possible pilot deviation.


Second narrative: During my descent out of 12;000 feet for 4;000 feet. I accidentally shut off the master avionics switch instead of the static deice which is right next to it. This shut down all navigation; communication as well as disconnected the auto pilot. I immediately turned avionics back on however it takes time before the Garmin 530 and 430 recycle as well as I have to acknowledge each test screen with 'OK'. The Garmin 600 PFD also changed its screen display and audio warned me through the headset the navigation is not available. During my attempt to recover the avionics I realized the auto pilot was also disengaged and the plane was now on a steep right turn approximately 60 degrees and steep descent. I could not make sense of the PFD so I used the backup attitude indicator to rectify the situation. I finally got the plane level and straight flight at that point Center was querying me to my change; which I still did not have navigation back.I explained my situation and was trying to reload my flight plan when ATC advised me to continue my descent and head back to my fix. At this point I was using my iPad with Foreflight to navigate back on course. Once I got everything restored ATC did ask me to call a phone number because there was another airplane close by. This did not cause the other plane to deviate and they did have me in sight per the transmissions over the radio. I did call the number and reported what happened. I am going to install a switch cover to avoid turning off the wrong switch.


Synopsis: ZAU Center Controller and pilot reported a GPS failure during IFR flight that resulted in a clearance deviation and airborne conflict.