Narrative:

While climbing through approximately FL220; I mentioned the poor climb performance we were getting with only 35 people in an xr. (700 FPM and 230 knots and accelerating very slowly). At around FL280 we observed an airspeed discrepancy flag. The first officer (first officer) began going through the QRH; while I flew. Near FL370 we were still troubleshooting when we began noticing rapidly changing differences in airspeed and altitude. We were IMC. My side began overspeeding while the first officer side was 50 or 60 knots less. I turned off the autopilot and we requested a descent and [advised ATC]. We were cleared to FL240. We observed only one abnormal message on EICAS descending through about FL290; 'interconnected weight on wheels inoperative'. We followed the guidance for descending with unreliable airspeed. We agreed we needed a VFR airport to divert to. At around 10000 feet my airspeed and altitude indications rapidly returned to something more normal. We continued visually and landed. The threats are fairly obvious. I think we should have decided sooner to stop the climb; however the deviations were relatively small until the last 1000 feet or so. We [advised ATC] very quickly which helped us out as far as getting a quick decent and help from ATC locating an airport. I think that another threat may have been very little cut and dried procedures for this type of event that was clearly marked/located in the QRH.turn the autopilot off; follow standby instruments immediately and not try to figure out which side is right or wrong. I think there should be an easy to find procedure with all the info needed in one spot for this abnormal.

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Original NASA ASRS Text

Title: The flight crew of a regional jet noticed an increasing discrepancy between their airspeed and altitude indications. It was determined that a pitot static anomaly existed and an immediate descent from IMC conditions was initiated. They advised ATC; diverted to a suitable alternate airport; and landed uneventfully.

Narrative: While climbing through approximately FL220; I mentioned the poor climb performance we were getting with only 35 people in an XR. (700 FPM and 230 knots and accelerating very slowly). At around FL280 we observed an airspeed discrepancy flag. The First Officer (FO) began going through the QRH; while I flew. Near FL370 we were still troubleshooting when we began noticing rapidly changing differences in airspeed and altitude. We were IMC. My side began overspeeding while the FO side was 50 or 60 knots less. I turned off the autopilot and we requested a descent and [advised ATC]. We were cleared to FL240. We observed only one abnormal message on EICAS descending through about FL290; 'Interconnected Weight On Wheels Inoperative'. We followed the guidance for descending with unreliable airspeed. We agreed we needed a VFR airport to divert to. At around 10000 feet my airspeed and altitude indications rapidly returned to something more normal. We continued visually and landed. The threats are fairly obvious. I think we should have decided sooner to stop the climb; however the deviations were relatively small until the last 1000 feet or so. We [advised ATC] very quickly which helped us out as far as getting a quick decent and help from ATC locating an airport. I think that another threat may have been very little cut and dried procedures for this type of event that was clearly marked/located in the QRH.Turn the autopilot off; follow standby instruments immediately and not try to figure out which side is right or wrong. I think there should be an easy to find procedure with all the info needed in one spot for this abnormal.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.