Aero Commander 500 Series
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Multiengine
Flight Crew Last 90 Days 540; Flight Crew Total 1800; Flight Crew Type 200
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control; Flight Crew Requested ATC Assistance / Clarification
Weather
I was in cruise flight at 3000 ft. and 25 miles East of MKC following a radar vector from KC approach to the ILS 3. There was moderate to heavy rime icing. I had a high power setting but my airspeed kept bleeding off until it got down to 120 knots. Turning became very sloppy and it started to seem like I was in an uncommanded turn. It felt like there was no rudder response. I called KC approach and asked them if their radar showed that I was making a turn. Before they responded the instruments showed the turn accelerating and I realized that the symptoms of a stall spin scenario. I pushed in on the yoke and pressed opposite rudder to recover from the stall and climb back up to 3000 ft. I lost about 700 ft of altitude before I recovered.I was using TKS fluid to get rid of the ice; but I had to ration my fluid because; I used it heavily on the initial trip [earlier] that night. There was freezing rain from 4000-6000 ft on that leg. I departed with 12 gallons of TKS fluid out of the 20 gallon limit. The plane that I was initially assigned to that night had a maintenance engine problem that I did not find out about until run up. I had to switch to a different plane. Normally; I take around 17 gallons of TKS; but on this night I chose to go with the minimum quantity for dispatch into known icing conditions. The plane that I switched to also had an electronic attitude indicator. Only a small number of planes in our fleet have them and they are not my preference but seem to work well enough. I find it harder to scan between the instruments with an electric AI because its brightness. I learned a few good lessons from this flight and am hoping to never have it happen again. For future flights I plan to fly at higher altitudes above the cloud ceiling. Altitude gives you more options and time to deal with a problem in icing. You can always use a slow descent to help increase your airspeed. Another change that I would have made is to ask for the ILS to 19 instead. I had time to observe the slow decrease in my airspeed and I should have requested the quickest approach since the winds were under 10 knots. The next time I have to switch planes right before a flight I am going add enough TKS fluid to make 17 gallons. It is better to be fully prepared for any scenario. Another change that I will make in the future is to always trust my instruments and make a slow emergency descent to gain airspeed if required. Next time something like this happens I plan to [advise ATC] right away.
AC50 pilot reported entering a stall and nearly a spin due to icing in IMC conditions.