Date: 202012
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Icing
Light: Daylight
Aircraft: Small Aircraft
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Cruise; Initial Approach
Airspace: Class E ZZZ2
ATC / advisory: Center ZZZ2
Aircraft component: AC Generator/Alternator
Component problem: Failed
Reporter organization: Air Taxi
Reporter function: Single Pilot; Pilot Flying; Captain
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Time Pressure; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Diverted; Flight Crew Became Reoriented; Flight Crew Landed in Emergency Condition
Contributing factors: Weather; Aircraft
Primary problem: Aircraft

Narrative: I departed ZZZ on an IFR flight plan to ZZZ1. The aircraft had sat for roughly 3 days over the weekend before this flight and was difficult to start that morning (battery seemed weak). 40 minutes into the flight; the first symptoms of an electrical malfunction began to show up. I was roughly 15 nm from the IAF for the RNAV XX approach into ZZZ1 at 8;000 feet MSL; in actual IMC with light to moderate rime icing. I had just switched from ZZZ2 Center to the CTAF for the ZZZ1 airport when the auto-pilot for the aircraft unexpectedly disconnected. All of the lights on the autopilot control panel went dark; and the autopilot would not turn back on. Initially; I decided to continue the approach by hand and have maintenance check the autopilot malfunction on the ground. After briefly troubleshooting the autopilot; I returned to my instrument scan. At first glance; my HSI indicated that I was on Heading/Course. Needles were centered and heading bug was situated at the top of the instrument. But when I looked over at the Garmin 430 GPS; it indicated that I was off heading by 20-30 degrees. By the time I looked back towards my HSI; there was a 'HDG' flag starting to flicker in the top right hand corner. I looked across the panel at the co-pilot's instrument cluster and noted that the co-pilot's artificial horizon was flopped over; indicating a 45* right bank and 20* nose up attitude. The co-pilot's side DG was also off by 90* from my magnetic compass. As I looked back towards the pilot's side instrument cluster; my HSI began spinning around and around like a top.At this point; I had obviously determined that several of my gyroscopic instruments had failed; and I had difficulty determining which instruments were trustworthy and which were not. From this point on; I did my best to maintain straight and level flight with my remaining instruments and the Garmin 430 GPS ground track. I looked out the window at my wings (I was still in IMC and light to moderate icing [at] this point) and saw that during my troubleshooting I had enough ice accumulation that small 'horns' of rime ice were begging to grow on the leading edges and my de-ice boots were mostly white with a layer of ice. When I pressed the switch on the overhead panel to activate my de-ice boots; nothing happened. I immediately switched back to ZZZ2 Center and [received priority]; advising them that I had gyroscopic instrument failures and inoperative anti-icing equipment. I requested an immediate climb in an attempt to escape the icing conditions and find visual flight conditions before my remaining instrumentation failed; along with vectors back to ZZZ (which I knew had good VFR weather conditions...ZZZ1 conditions appeared to be worsening when I had last listened to the automated weather). ATC was extremely helpful and professional. Immediately offering any assistance they could; giving me no-gyro vectors towards ZZZ and approving a climb to 12;000 feet MSL. I had difficulty maintaining a heading and climb pitch-attitude initially; but got vaguely stabilized within a few minutes. Once stabilized; I noticed that the left alternator light was on; I attempted to re-cycle the alternator master switch twice without success. I then began to load-shed all electrical equipment which was not absolutely necessary for the continuation of the flight; and I advised ATC that I had experienced an alternator failure. 	I initially broke out of the top of the cloud layer and entered VMC around 10;000 feet roughly 15 minutes after the first indication of electrical failure. I had to request a higher altitude shortly thereafter as the tops of the clouds sloped higher towards ZZZ. ATC cleared me for a block altitude 8;000 feet to 12;000 feet; then eventually up to 14;000 feet; and authorized any course deviations necessary for me to remain in VFR conditions.Upon leveling off; I was initially concerned about what appeared to be a fairly significant performance loss. My first assumption was that it was due to ice build up on the wings/tail. In a level flight attitude; at 38 of manifold pressure and 2400 rpm (typical climb power) I was only getting 120 knots indicated airspeed. 160 knots to 170 knots indicated is more typical during cruise flight at a much lower power setting (30'/2300rpm). I alerted ATC that I was seeing abnormally low air speeds. But after a quick glance at my GPS (which was showing a 230 knots ground speed) I realized that the airspeed discrepancy was most likely due to pitot icing. ATC confirmed that they were showing me with a ground speed in the high 220's. By this point; the aircraft was out of icing conditions and flying just fine in VMC. So most of the potential danger had past. The last thing I had to do was search around for a hole in the clouds so that I could get back into ZZZ (there was an overcast layer between my aircraft and the ground). With the help of ZZZ3 Approach; ZZZ Tower; and several other aircraft in the area giving pilot reports; I found an opening near ZZZ4 and circled down for a visual approach into Runway XXL at ZZZ. The vast majority of the ice which had accumulated on the aircraft came off in the decent due to higher airspeeds and increasing temperatures. I landed without further incident; parked the aircraft; and immediately took down notes regarding the order of events while they were still fresh in my mind. I then called the Chief Pilot to relay what happened."




Synopsis: Single air taxi pilot in IMC and icing conditions reported an alternator failure.