Date: 201904
Local time of day: 1201-1800
Location: ZID.ARTCC, IN
Aircraft: Small Aircraft
Operating under: Part 91
Flight plan: IFR
Flight phase: Cruise
Airspace: Class E ZID
ATC / advisory: Center ZID
Reporter organization: Government
Reporter function: Enroute
Human factors: Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed As Precaution
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: Aircraft X contacted ZID to report they were picking up light rime icing and requested a descent. I looked at the MVA and the lowest for his course of flight would eventually be 4;500 ft. MSL. Aircraft X started to descend. At 4;500 ft. MSL; Aircraft X got out of the icing temporarily. I issued weather to the pilot to expect moderate precipitation for next 100 miles. I asked the pilot if they had any de-icing or anti-icing equipment on board. They said Negative. I suggested to the pilot an airport at their 8-7 o'clock and 5 miles; to land at due to the weather up ahead. I also said there were 4-5 airports he could land at along his route. He came back with they were just getting out of the icing and a +1 degree Celsius and liked lower. I descended them to 4;000 ft. MSL. Another aircraft; Aircraft Y; requested to speak; I let them; Aircraft Y spoke and told the aircraft to 'take his advice; land; it's not worth it.' I descended Aircraft X to the MVA 3;700 ft. MSL. I told Aircraft X about the several airports he could land at including Scott Municipal at a 200 heading and 18 miles. I told the pilot that if he were to continue to SCX; that the lowest I could go in that area was 4;500 ft. MSL unless he [advised ATC]. Aircraft X decided that he wanted to divert to SCX and [advised ATC]. I read the SCX airport weather to him; there was only 1 NOTAM not pertinent to the safety of flight that was not read. I asked if he could climb to at least 4;500 MSL to attempt the approach (The approach actually required to be started at 4;800 MSL). Aircraft X said negative. I cleared Aircraft X to COPEP and told him to expect the RNAV 23 approach into SCX. He read it back; but never turned. COPEP turned Aircraft X back into the weather and kept him in the freezing conditions longer. Aircraft X started to descend. I asked Aircraft X if they had ground contact. They said no; and then when the aircraft was leaving 2;800 ft. MSL they said they could see the ground. I told them that the SCX airport was now a 195 heading and 4.8 miles. They called the airport in sight at 2;500 ft. MSL. I said Roger; paused; key up and cleared Aircraft X for the visual approach. I attempted to ask several times for the souls on board and fuel on board remaining. I was able to get 2 souls on board; but no report of FOB remaining. I called in the blind for Aircraft X Charlie a few times to ask their progress; and a [air carrier] keyed up to say they could hear Aircraft X trying to call Center on our frequency to say they landed safely.	SME airport was another option the aircraft could navigate to; with better weather and the possibility of not descending below the MVA to reach the airport and stay out of icing conditions. I did not call a Low Altitude Alert clearance to Aircraft X when he descended below the MVA. Given the situation would rise again; I should take all the options into consideration.




Synopsis: ZID ARTCC Controller reported that an aircraft was in icing conditions and the process that was taken to get the aircraft safely on the ground.