Narrative:

While flying at FL360 we first received stabilizer cold right cas followed by inbd wing a/I cold lr cas messages. We followed the checklist and no change. We asked for the tops; but they were well above us. We then received engine control fault lr cas messages. We did not observe ice visually; but we requested lower just in case. We were cleared to FL320. These cas messages eventually cleared.we next observed [different] IAS on both pfds. We followed the checklist and went to reversion mode as the left side appeared in error while the right side and the standby agreed. This seemed to fix this problem. We requested lower to get to warmer air. We got FL270. Our original cas messages reappeared and we asked for much lower. We then got FL200. As we descended to this; I noticed the airspeed on both pfds was decreasing as we descended while the power was 80% N1 and the aoa was normal for this descent attitude and the standby IAS was 300. This prompted us to request 11;000 even though we were between layers with no visible ice.in the lower 20s both pfds read 30 IAS then they soon gave up. We had red xs on the airspeed and altimeter of both pfds. At this point we [advised ATC of the situation] as we lost all primary airspeed and altimeter readings. We were referencing the standby indications and aoa along with ATC ground speed verification. We continued down to 4;000 feet [and] the primary airspeed and altimeter returned. Everything appeared normal until on a 7 mile final. We observed the left pfd 20 knots faster than the standby and the right pfd 10 knots faster than the standby. The standby felt correct and most closely agreed with the ground speed. We used this for an uneventful landing.I'm not sure what caused the original cas messages as the flight down [we flew] through the same weather system [all] was uneventful with all anti ice systems working normally. Talking with the mechanics; it is suspected there was water which got caught in the pitot static system and froze which would not allow the normal anti ice heaters to rid this. I'm so glad we practiced the [other air carrier pitot ice] scenario in the simulator as this was exactly what we experienced!

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Original NASA ASRS Text

Title: CE-680 First Officer reported loss of primary airspeed and altimeter indications. Maintenance suspects water trapped in the pitot/static system that then froze at altitude.

Narrative: While flying at FL360 we first received STAB COLD R CAS followed by INBD WING A/I COLD LR CAS messages. We followed the checklist and no change. We asked for the tops; but they were well above us. We then received Engine Control fault LR CAS messages. We did not observe ice visually; but we requested lower just in case. We were cleared to FL320. These CAS messages eventually cleared.We next observed [different] IAS on both PFDs. We followed the checklist and went to reversion mode as the left side appeared in error while the right side and the standby agreed. This seemed to fix this problem. We requested lower to get to warmer air. We got FL270. Our original CAS messages reappeared and we asked for much lower. We then got FL200. As we descended to this; I noticed the airspeed on both PFDs was decreasing as we descended while the power was 80% N1 and the AOA was normal for this descent attitude and the standby IAS was 300. This prompted us to request 11;000 even though we were between layers with no visible ice.In the lower 20s both PFDs read 30 IAS then they soon gave up. We had red Xs on the airspeed and altimeter of both PFDs. At this point we [advised ATC of the situation] as we lost all primary airspeed and altimeter readings. We were referencing the standby indications and AOA along with ATC ground speed verification. We continued down to 4;000 feet [and] the primary airspeed and altimeter returned. Everything appeared normal until on a 7 mile final. We observed the left PFD 20 knots faster than the standby and the right PFD 10 knots faster than the standby. The standby felt correct and most closely agreed with the ground speed. We used this for an uneventful landing.I'm not sure what caused the original CAS messages as the flight down [we flew] through the same weather system [all] was uneventful with all anti ice systems working normally. Talking with the mechanics; it is suspected there was water which got caught in the pitot static system and froze which would not allow the normal anti ice heaters to rid this. I'm so glad we practiced the [other air carrier pitot ice] scenario in the simulator as this was exactly what we experienced!

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.