Date: 201510
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pitot-Static System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Troubleshooting; Distraction; Confusion
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution; Flight Crew FLC Overrode Automation; Flight Crew Diverted; Flight Crew Became Reoriented
Contributing factors: Aircraft; Weather
Primary problem: Aircraft

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.


Second narrative: We took off with no problems. Upon passing through FL220 we noticed the aircraft not climbing very well. We were getting about 700 feet per minute in an XRJ. We talked about it and noticed the airspeeds didn't match. As we progressed; the airspeed deviations started to grow. We now turned to the QRH to seek guidance. The Captain side PFD was showing close to overspeed; while my side was showing slowing. We were now through FL360 with 1000 feet to go. The plane was stating high speed from the Captain side; but we were still slowing. We decided to [advise ATC] and started an immediate descent. I told ATC that we needed to be VFR soon as we could not trust our primary instruments. We decided on a diversion airport [that] was VFR and descended visually. Around 10;000 feet the Captain side started to respond to the blockage and things started to scroll back to their proper values. We landed without incident and reported to maintenance.Losing our Pitot-Static system on both of our PFD's causing us to rely on VFR flight rules and our backup instruments.


Synopsis: 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.