Date: 202001
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Cloudy; Icing; 8
Light: Daylight
Aircraft: Citationjet (C525/C526) - CJ I / II / III / IV
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
Airspace: Class G ZZZ
ATC / advisory: CTAF ZZZ
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Weather; Airport
Primary problem: Airport

Narrative: This incident occurred shortly after XA:00 local time. Winds were calm and I selected RWY 22 due to weather/cloud conditions rather than circle to 4. A cloud layer at 2;100 had been reported on previous AWOS.From the air; I could see that there was contamination on the runway and had heard the previous pilots land without incident. There were no NOTAMs published or information available on AWOS regarding runway conditions. I requested from CTAF runway information but received no information. As I turned onto final; I was extremely vigilant with my reference speed and touchdown zone. When I crossed the threshold; the plane floated for a moment and we touched down. The runway length was approximately 7;000 feet total. Landing performance with contaminated runway was within limits.I deployed ground spoilers; waited for the airplane to decelerate and started applying brakes. At that point; we moved slightly left and as I continued to apply and use rudder the aircraft went into a slide and exited on the left side of the runway. When we entered the slide; I had zero control. I had about 3;500 feet left when we started to aggressively slide off; the aircraft coming to a halt about 1;500-2;000 feet prior to the end.  Human factors would include single pilot operations and not having the time to communicate with the FBO about additional runway conditions. The pilot ahead of me did request this information and was told the runway was a 5. When I spoke with him; he said that it was definitely a 3 and while they didn't apply brakes (KingAir); it was apparent it was very slippery.When we exited the aircraft; I immediately inspected the runway conditions and they were exceptionally icy. The type of ice that is created when a plow moves over the surface close to the ground and leaves a uniform and smooth surface. In addition; the areas that were clear; had ice. So while it appeared patchy; I believe the surface was largely ice.From an operational standpoint; having better information from the ground would have vastly changed my decision. From my perspective; I would not land on a runway that is only a 3. It was an easy diversion to ZZZ1 and we were planning on this in the event conditions were within our limits.In trying to assess all possible contributing factors; had weather conditions been more favorable; RWY 4 would have been a better option as we could have assessed the runway conditions as well as had more time to assure a stabilized approach. I broke out of the clouds early enough to safely descend to RWY 22 however; more time in this situation is always better.




Synopsis: C525 single pilot reported a runway excursion after landing due to icy runway conditions.