Skylane 182/RG Turbo Skylane/RG
Flight Crew Instrument; Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 112; Flight Crew Total 1378; Flight Crew Type 30
Situational Awareness
Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Human Factors; Weather
During flight unexpected moderate rime ice was encountered. Upon encountering the ice I requested a higher altitude of 13;000 [feet] to attempt to escape the conditions which ATC approved. However; at that point; buildup had accrued and the aircraft was struggling to maintain 12;000 [feet]. I then requested 11;000 [feet]which Center also approved. The aircraft continued to have difficulty maintaining altitude and fell below the minimum IFR altitude for the area several times resulting in a terrain alert and several terrain vectors from ATC. An aircraft coming from the other direction advised that the area a couple miles ahead from the aircraft's current position was clear; so I elected to get to that area and the rest of the flight was completed normally. Lack of positive icing PIREPs in the vicinity of the route of flight informed that encountering icing would be unlikely. In the area where the icing occurred it seemed that the combination of location and temperature were contributing factors.
C182 pilot reported receiving terrain alerts when his aircraft was unable to maintain safe altitude because of ice accumulation.