EMB ERJ 145 ER/LR
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action; General Maintenance Action
Aircraft
At FL329; Captain's airspeed indicator dropped from approximately 280kts to 115kts and altimeter stopped indicating. Controls transferred to FO (First Officer) side; QRH was completed and performance tables referenced. Momentary altitude deviation. ATC alerted. Landed normally and contacted Dispatch and Maintenance.
Cruising at FL 320 PF (Pilot Flying) (Captain in training) noticed airspeed slowly bleeding off then rapidly bled off. Upon getting IAS comparator flags PF called for PM (Pilot Monitoring) to get out unreliable airspeed QRH. Airplane started pitching up and looking down noticed ALT comparator flag as well on PF side. Transferred controls of the plane to PM noticing his side appeared to be working fine. Notified ATC of unreliable airspeed and altitude deviation.  Requested descent to get out of clouds. ATC told us to descend FL 220. Jumpseat pilot had unreliable QRH pulled up on tablet and handed it to upgrade training CA (now PM) to run checklist. Descended down to FL 220 and just before reaching altitude airspeed and altitude came back on CA side. LCP (Line Check Pilot) in FO seat continued to fly and landed without incident.
Flight Crew reported airspeed indications became unreliable at cruise so they descended and airspeed returned to normal.