Narrative:

We were flying at FL360 and had just been cleared to descend to FL300 by ATC. As we started the descent we heard the aural caution chime and saw the message sps advanced appear on the EICAS. At this moment we both noticed that the captain's airspeed tape was winding down rapidly and the IAS indication appeared on the airspeed tape. We saw the first officer side airspeed was reading higher and was stable. The aircraft began to pitch farther forward and the captain; who was pilot flying; disconnected the autopilot. After this was down we received further EICAS messages IC1 wow fail and autopilot fail. The first officer began looking at the QRH for the IC1 wow message. Both crewmembers saw that the first officer side indications were matching the isis indications; while the captain's side indications of both speed and altitude were different. At this point the captain transferred control to the first officer and re-coupled the flight director to the first officer's side as she couldn't see the first officer side pfd well due to glare. We leveled at FL300 as instructed. When the flight director was re-coupled to the first officer side both the IC1 wow and sps advanced messages cleared; and the captain's side instruments began displaying normally again. The captain called ATC and asked them to confirm our indicated altitude at FL300 and they agreed with us. We reset the autopilot by holding the quick disconnect for three seconds per the QRH. This cleared the autopilot fail message. At this point we discussed needing to request a lower altitude to get out of rvsm airspace; when ATC gave us a descent to FL240. We started down; and while descending re-coupled the flight director to the captain's side; re-engaged the yaw damper and when everything appeared to be working normally; re-engaged the autopilot. Flight control was transferred back to the captain; and the rest of the flight was completed normally. Maintenance was contacted via ACARS; and then via radio. We discussed the issue with maintenance once on the ground and they thought that it might be related to a faulty IC600. The captain wrote up the discrepancy and maintenance is looking into it.there were some small circuit breaker buildups in the area; but we were in VMC at the time. ATC radio traffic was low and there were no other aircraft in our vicinity. The primary threat was that we had questionable airspeed and altitude data. The captain made a good decision in transferring control to the first officer and the aircraft was leveled at the assigned altitude without any deviations. The only thing I would consider as an undesired aircraft state was that we were then flying in rvsm airspace without a functioning autopilot. After we confirmed our altitude and determined that we had functional flight instruments to work with; we were about to address the rvsm issue when ATC gave us a lower altitude; resolving that situation. The captain did a good job in identifying that the aircraft wasn't doing what she had commanded; and disconnecting the autopilot. The focus was to fly the airplane first; then fix the problem. This is definitely the best way to address an automation/flight control issue.

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Original NASA ASRS Text

Title: An EMB-145 EICAS alerted SPS ADVANCED while the Captain's airspeed and altimeter malfunctioned at FL360 so the First Officer; with stable instruments; flew until the Captains' instruments returned. Maintenance believed the IC600 malfunctioned.

Narrative: We were flying at FL360 and had just been cleared to descend to FL300 by ATC. As we started the descent we heard the aural caution chime and saw the message SPS Advanced appear on the EICAS. At this moment we both noticed that the Captain's airspeed tape was winding down rapidly and the IAS indication appeared on the airspeed tape. We saw the First Officer side airspeed was reading higher and was stable. The aircraft began to pitch farther forward and the Captain; who was pilot flying; disconnected the autopilot. After this was down we received further EICAS messages IC1 WOW FAIL and AUTOPILOT FAIL. The First Officer began looking at the QRH for the IC1 WOW message. Both crewmembers saw that the First Officer side indications were matching the ISIS indications; while the Captain's side indications of both speed and altitude were different. At this point the Captain transferred control to the First Officer and re-coupled the flight director to the First Officer's side as she couldn't see the First Officer side PFD well due to glare. We leveled at FL300 as instructed. When the flight director was re-coupled to the First Officer side both the IC1 WOW and SPS advanced messages cleared; and the Captain's side instruments began displaying normally again. The Captain called ATC and asked them to confirm our indicated altitude at FL300 and they agreed with us. We reset the autopilot by holding the quick disconnect for three seconds per the QRH. This cleared the AUTOPILOT FAIL message. At this point we discussed needing to request a lower altitude to get out of RVSM airspace; when ATC gave us a descent to FL240. We started down; and while descending re-coupled the flight director to the Captain's side; re-engaged the yaw damper and when everything appeared to be working normally; re-engaged the autopilot. Flight control was transferred back to the Captain; and the rest of the flight was completed normally. Maintenance was contacted via ACARS; and then via radio. We discussed the issue with maintenance once on the ground and they thought that it might be related to a faulty IC600. The Captain wrote up the discrepancy and maintenance is looking into it.There were some small circuit breaker buildups in the area; but we were in VMC at the time. ATC radio traffic was low and there were no other aircraft in our vicinity. The primary threat was that we had questionable airspeed and altitude data. The Captain made a good decision in transferring control to the First Officer and the aircraft was leveled at the assigned altitude without any deviations. The only thing I would consider as an undesired aircraft state was that we were then flying in RVSM airspace without a functioning autopilot. After we confirmed our altitude and determined that we had functional flight instruments to work with; we were about to address the RVSM issue when ATC gave us a lower altitude; resolving that situation. The Captain did a good job in identifying that the aircraft wasn't doing what she had commanded; and disconnecting the autopilot. The focus was to fly the airplane first; then fix the problem. This is definitely the best way to address an automation/flight control issue.

Data retrieved from NASA's ASRS site as of July 2013 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.