Date: 202001
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Icing; Rain; Cloudy
Light: Daylight
Aircraft: Cessna 402/402C/B379 Businessliner/Utiliner
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class C ZZZ
Aircraft component: Window Ice/Rain System
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; Flight Crew Took Evasive Action; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Weather; Procedure
Primary problem: Weather

Narrative: I was boarding the aircraft when a my destination airport changed a NOTAM at my destination airport closing the runway until a further time that day; at the time I was in the aircraft boarding my passengers as I had received an IFR clearance to my destination 10 minutes before. While I was departing the area VFR on an IFR clearance I encountered moderate turbulence below 9000 ft. I reported the weather conditions to both ARTCC and [Operations Control]. At 9000 ft. I entered Icing conditions and requested a higher altitude to get out of the ice. I was assigned 11000 ft. and once established in cruise approximately 50NM from billings I was advised by ARTCC that ZZZ my destination airport had just reported both runway closures and to advise of intentions. I contacted [Operations Control] of the situation and suggested a possible diversion to ZZZ1 instead so as to shuttle the passengers to ZZZ and return back REPO. They liked the plan and said they would contact ZZZ1 to gain conditions and see if they could organize passenger transport. I advised my passengers of the situation. I then was contacted by [Operations Control] that the situation was also bad in ZZZ1 and they too intended to close the runway. I then advised ATC a return to ZZZ2. Shortly after this radio communication I encountered Freezing Rain I advised ATC of the weather conditions and [Operations Control] I also requested a decent to get out of icing conditions. Shortly after this I noticed the annunciation panel was black during windshield operation and noticed the ice was not coming off the windshield. I complied with the QRH and [Requested Priority Handling] with ARTCC due to windshield anti-ice failure. I notified [Operations Control] and got into contact with the ZZZ2 station Manager and advised him of the weather conditions in the area at the diversion airport and of the priority situation. After descending several thousand feet the ice did not clear. I requested ATC give me a lower altitude to try and reach above freezing altitude. At approximately 6000 ft. the windshield ice broke off and I continued with a Visual Approach to Runway XX. After I landed and taxied in I spoke with the passengers: [airport rescue and firefighting]; [Operations Control]; Dispatch; [Maintenance Control]; Station Manager and Station Supervisor about the situation. I made a maintenance log book entry and complied with company policy and procedure to secure the aircraft at the hanger.Windshield De-ice/Anti-Ice Circuit Breaker tripped in icing conditions. For weather diversion(s); unforecasted adverse weather.One thing I could have done to avoid the situation with the diversions would be to check the NOTAMs at flight time so as to make sure that inclement weather changes do not change runways conditions from open to closed.




Synopsis: Pilot reported weather and a closed destination airport required an air turnback; during which windshield anti ice failed.