Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Commercial; Flight Crew Instrument
Troubleshooting; Workload
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action
Aircraft; Weather
Completed pre-flight and morning run-up all de-ice and anti-ice protection was functioning normally. Prior to departure I turned on prop anti-ice; stall heat; and pitot heat due to icing conditions aloft. On departure encountered heavy to moderate precipitation on departure; and continuous light chop with occasional moderate turbulence reported by [another aircraft] and myself. Upon climbing through 5;500 encountered trace icing. The icing grew in intensity through the climb through to 9;000 MSL; at which I requested a climb to 11;000 MSL. Center said they had the request and to wait for amplitude. During the cruise checklist I discovered the prop anti-ice switch breaker had tripped to the off position then reset it. After the completion of the checklist the switch breaker had deactivated the switch a second time. At this point in continuous light icing with moderate precipitation I [notified] ATC; advising them that I had a prop anti-ice protection failure and then reaffirmed that I was in icing conditions without anti-ice protection. I then requested a descent while activating the boots several times and increasing my available power in the descent [to] account for the degraded performance on the props. I descended to lower altitudes as advised by ATC and requested lowest available altitude do get out of the icing. When ATC assigned 5;300 MSL I left icing conditions into moderate precipitation; at about 5;400 icing stopped. Emergency vehicles were dispatched and standing by as well as followed us in to the gate. I advised all ATC; [Maintenance and Operations Control] about the situation. Post flight all passengers at gate were queried if they were ok and talked with ARFF (Airport Rescue and Fire Fighting) personnel; as well as discuss with [Operations Control and the Chief Pilot] and elected to end duty day due to IMSAFE checklist.Successful 'trip' of the PROP ANTI-ICE switch breaker to protect the electrical system from prop anti-ice failure.
C402 pilot reported propeller anti-ice system failed after entering icing conditions.