Date: 201708
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Icing
Light: Daylight
Aircraft: Caravan Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Initial Approach
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Time Pressure
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Executed Go Around / Missed Approach
Contributing factors: ATC Equipment / Nav Facility / Buildings; Weather
Primary problem: Weather

Narrative: The flight was being conducted IFR. The cloud tops were at approx. 7500 feet. When I was cleared for the approach by Center I requested a climb to 8000 ft; instead of the published 2000 ft; in the event of a missed approach; because I knew that I would be unable to communicate with Center at 2000 ft. While descending for the approach I noticed that I was accumulating a large amount of ice on the airframe; at an unusually fast speed; and that it was moving behind the boots. I 'blew the boots' in an effort to clear the wings. The boots were not able to keep up with the accumulation of ice and I could not clear the wings. I believed that the situation was becoming dangerous; and that I needed to get out of the icing layer as fast as possible. I decided to execute a missed approach. I was unable to communicate with Center to inform them of my going missed; so I contacted ZZZ Radio on the Remote Communications Outlet (RCO) frequency of. The RCO is only good for about a 5 mile radius of [my position]; so I knew I didn't have a lot of time. I told ZZZ radio that I was going missed and requested to go direct to ZZZ at 8000 ft due to heavy icing. This request was denied; and I was instructed to fly the published missed at 8000 ft. I then lost comms with ZZZ Radio. While trying to climb to 8000 ft I began to accumulate ice on the airplane at an even faster rate. The windshield was completely covered and I was quickly losing airspeed. All anti-ice and de-ice equipment was ON. At 4000 ft I was unable to climb anymore and my airspeed was still decaying. I was still unable to communicate with Center or ZZZ Radio. I scanned my ADSB and noticed that [another company pilot] was in my area. I contacted him. Communication with him was spotty and difficult. I asked him to relay to Center that I was unable to climb; was in severe icing conditions; and was in an emergency. I also requested a descent to 1000 ft; and a course deviation towards the shoreline so I could maintain over-water gliding distance. This request was granted by Center. I descended; and broke out of the layer at about 1500 over the shoreline. The temp was +2C at that altitude. Most of the ice sublimated off of the airplane while returning to ZZZ; and I was able to safely land in ZZZ with ice free wings. After landing; I called ZZZ Radio and Center. I thanked them for the help and asked if they needed any information regarding the incident. They both responded that no additional information was needed.Lack of radio coverage in the area made this incident more difficult to deal with. A more powerful RCO would have helped also.




Synopsis: C208 pilot reported a missed approach when the aircraft iced up on approach to the destination airport; was unable to climb above 4000 feet; requested a descent and returned to departure airport.