Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Aircraft; Weather
We were flying in IMC and received an IAS comparator on both the Captain and F/O (First Officer) PFD (Primary Flight Display). About 30 seconds later the autopilot disconnected. We knew that we had an Unreliable Airspeed. The F/O continued to fly the plane and we went through [the] unreliable airspeed checklist.  We then spoke with ATC and received a block altitude. We then went through the QRH procedure for unreliable airspeed. We determined that the Captain's airspeed was inoperative. We completed the checklist pulling from the F/O CADC (Central Air Data Computer). We got #2 Autopilot and NAV working. The Captain landed the airplane without any issues.Cause: We believe the Captain's pitot tube could have been frozen when we were flying in IMC.
MD-11 Captain reported his airspeed indicator became unreliable; possibly due to pitot icing.