Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Diverted; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft; Weather
First Officer flying through FL200 on way to FL270; in IFR conditions. First Officer and Captain's airspeed indicators [were] unreliable. Standby airspeed indicator correct. Captain's airspeed indicator came back; but First Officer's out for 5 minutes and EEC (Electronic Engine Control) Systems went to Standby. QRC and QRH procedures accomplished as well as followup procedures. Anti-icing systems working; Engine and wing heat on. Stayed as much out of weather; ZZZ closed; ZZZ1 still in VFR weather and location of heavy maintenance for the B-737. Briefed flight attendants and passengers. Captain flew to ZZZ1; safety vehicles checked out aircraft.Good crew coordination of verification of the unreliable airspeed indicators.Don't fly into clouds with icing conditions. May have been multiple problems that happened at the same time. EEC Systems went to standby while in heavy thick clouds; on climb out; through the freezing level.
Captain reported diverting after airspeed indications became unreliable in IMC conditions and the destination airport closed.