Date: 202008
Local time of day: 1201-1800
Location: ZHU.ARTCC, TX
Weather elements / visibility: Icing; Rain; Thunderstorm
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZHU
ATC / advisory: Center ZHU
Aircraft component: Pitot-Static System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Aircraft Other Automation
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Weather
Primary problem: Weather

Narrative: We departed MSY in VMC with an area of rain showers and thunderstorms to the South and South West along our route of flight.Through route study and crew briefings we knew this weather would impact the first 20-30 minutes of our flight. Center advised us of moderate to extreme precipitation at our twelve o'clock. We received clearance for left and right deviations of course and told to proceed direct when able. We chose a clear path initially but reached the point in the flight we would have to proceed carefully. The clouds and rain showers began to obscure the flight path and we relied further on our satellite based and onboard weather radar. Engine thermal anti ice was on. As we were passing through FL280 the rain picked up and my windshield and wiper began to freeze over. Simultaneously the Captain's airspeed indicator gave erroneous low air speed readings 100-140 KIAs; IAS DISAGREE was displayed; and 'AIRSPEED TOO LOW' was announced. My instruments appeared to be the most accurate and I assumed pilot flying duties. The autopilot disconnected due to my physical intervention maintaining pitch. I announced my intention to maintain 6 degrees nose high in the climb to FL370 and leave the throttles at the climb limit thrust. I then disconnected the auto throttles as they began to retard. Due to the severe icing; I scanned the engine instruments and found no indications of reduced thrust. Next; it was time to navigate. We had to make small turns to avoid the worst of the embedded towering cumulus cells being returned on the weather radar. These developed along our path as we were deviating. We decided to press ahead to be clear of the weather in a few minutes instead of the longer path of turning around. We also amended our top of climb lower to FL330 to avoid being closer to MMO (Maximum Operating Limit Speed) with suspect instrumentation. We were climbing at about 280 KIAS. Upon reaching FL330; I leveled the aircraft and in a few miles we exited the weather. The CA's (Captain's) airspeed indicator returned to normal and we ran the Airspeed Unreliable QRC and QRH. Since icing was the suspected cause of the fault and the airspeed indicator was no longer unreliable we reengaged the autopilot; observed the flight path; reengaged the auto throttles; observed the flight path; and continued normally to our destination.Not correctly considering vaulted moisture in weather radar settings and no indications of super-cooled liquid droplets in WSI (Weather Services International).[I recommend] better WSI capabilities to display simultaneous types of weather information; i.e. icing and radar.


Second narrative: Departed MSY in VMC with an area of rain showers and thunderstorms to the South and South West along our route of flight.Through route study and crew briefings we knew this weather would impact the first 20-30 minutes of our flight. Center advised us of moderate to extreme precipitation at our twelve o'clock. We received clearance for left and right deviations of course and told to proceed direct when able. We chose a clear path initially but reached the point in the flight we would have to proceed carefully. The clouds and rain showers began to obscure the flight path and we relied further on our satellite based and onboard weather radar. Engine thermal anti ice was on. As we were passing through FL280 the rain picked up and my First Officer's windshield and wiper began to freeze over. Simultaneously the Captain's airspeed indicator gave erroneous low air speed readings 100-140 KIAs; IAS DISAGREE was displayed; and 'AIRSPEED TOO LOW' was announced. My instruments appeared to be the most accurate and the first officer assumed pilot flying duties. The autopilot disconnected due to the physical intervention maintaining pitch. The FO (First Officer) announced his intention to maintain 6 degrees nose high in the climb to FL370 and leave the throttles at the climb limit thrust. He then disconnected the auto throttles as they began to retard. Due to the severe icing; I scanned the engine instruments and found no indications of reduced thrust. Next; it was time to navigate. We had to make small turns to avoid the worst of the embedded towering cumulus cells being returned on the weather radar. These developed along our path as we were deviating. We decided to press ahead to be clear of the weather in a few minutes instead of the longer path of turning around. We also amended our top of climb lower to FL330 to avoid being closer to MMO (Maximum Operating Limit Speed) with suspect instrumentation. We were climbing at about 280 KIAS. Upon reaching FL330; the FO leveled the aircraft and in a few miles we exited the weather. The CA's (Captain's) airspeed indicator returned to normal and we ran the Airspeed Unreliable QRC and QRH. Since icing was the suspected cause of the fault and the airspeed indicator was no longer unreliable we re-engaged the autopilot; observed the flight path; re-engaged the auto throttles; observed the flight path; and continued normally to our destination.Weak or inoperative pitot heat; however we had no indications that the heat was inoperative.I don't know that there was any way to avoid this particular incident. The only changes that I would of made is I would have [requested priority handling].


Synopsis: B737-8 flight crew reported unreliable airspeed indications during heavy precipitation.