Narrative:

Neither captain nor first officer are sure what caused the emergency. After completing a walk around after the flight; the first officer did not see anything wrong with any pitot tube or static port. Even though it is unlikely at FL340; it is possible that icing had started to occur and the automatic deicing system did not turn on. As stated above; captain and first officer agreed to turn icing to on position and not long after the speeds appeared to return to normal. About 45 minutes after departure from ZZZ; at FL340; IAS amber indication appeared on both captain and first officer speed tape. Pilot monitoring (pilot monitoring) began work on QRH. Then sps (stall protection system) advanced caution message appeared on the EICAS. Pilot monitoring also began work on that in QRH. Pilot monitoring determined his pitot static system was outputting incorrect information to his speed tape. It was indicating between 15-20 knots slower than standby and pilot flying (pilot flying) speed tapes. Pilot monitoring pressed air data computer button and his speed tape began to match the others. Pilot monitoring alerted ATC of the issue. ATC told us to descend to 17000 feet and maintain 290 kts or greater. As pilot flying began descent; he noticed that his speed tape was not accurate based on the chosen descent rate and power setting. Both pilot flying and pilot monitoring speed tapes started to decrease speed rapidly but standby speed remained constant. Pilot monitoring and pilot flying decided to turn anti-ice system to on position while continuing descent. After reaching an altitude with visual conditions; both pilot flying and pilot monitoring speed tapes began to 'work.' pilot monitoring informed ATC of this but still requested fire teams to be waiting at runway. Pilot flying maintained a slightly higher airspeed throughout flight to guarantee no stall would occur in case speed tapes were misinforming still. Landing was completed on [runway] xxl at ZZZ1. Pilot flying maintained higher speed on approach with accordance to sps advanced QRH requirements + additional speed for same reasons stated above. Pilot flying landed the aircraft and began decelerating with breaks and thrust reversers. Just before transferring pedal controls to the captain; pilot flying noted the breaks started working poorly. After captain had control of aircraft; a number of hydraulic fail messages appeared on the EICAS. Captain was unable to steer and struggled to slow for a few seconds; but hydraulics kicked back on and we were able to taxi to the gate with no further issues. This hydraulic issue had also occurred on the previous flight. Maintenance had defered the automatic electronic hydraulic pump position. We were told to take off and land with the electronic hydraulic switch to on; which was completed; but this did not change the outcome after landing in ZZZ1.

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Original NASA ASRS Text

Title: The pilot of an E145 reported that the airspeed indicators were unreliable in flight. Upon landing; the aircraft had a momentary hydraulic failure.

Narrative: Neither Captain nor First Officer are sure what caused the emergency. After completing a walk around after the flight; the First Officer did not see anything wrong with any pitot tube or static port. Even though it is unlikely at FL340; it is possible that icing had started to occur and the automatic deicing system did not turn on. As stated above; Captain and First Officer agreed to turn icing to ON position and not long after the speeds appeared to return to normal. About 45 minutes after departure from ZZZ; at FL340; IAS amber indication appeared on both Captain and First Officer speed tape. Pilot Monitoring (Pilot Monitoring) began work on QRH. Then SPS (Stall Protection System) advanced caution message appeared on the EICAS. Pilot Monitoring also began work on that in QRH. Pilot Monitoring determined his pitot static system was outputting incorrect information to his speed tape. It was indicating between 15-20 knots slower than standby and Pilot Flying (Pilot Flying) speed tapes. Pilot Monitoring pressed ADC button and his speed tape began to match the others. Pilot Monitoring alerted ATC of the issue. ATC told us to descend to 17000 feet and maintain 290 kts or greater. As Pilot Flying began descent; he noticed that his speed tape was not accurate based on the chosen descent rate and power setting. Both Pilot Flying and Pilot Monitoring speed tapes started to decrease speed rapidly but standby speed remained constant. Pilot Monitoring and Pilot Flying decided to turn anti-ice system to ON position while continuing descent. After reaching an altitude with visual conditions; both Pilot Flying and Pilot Monitoring speed tapes began to 'work.' Pilot Monitoring informed ATC of this but still requested fire teams to be waiting at runway. Pilot Flying maintained a slightly higher airspeed throughout flight to guarantee no stall would occur in case speed tapes were misinforming still. Landing was completed on [Runway] XXL at ZZZ1. Pilot Flying maintained higher speed on approach with accordance to SPS Advanced QRH requirements + additional speed for same reasons stated above. Pilot Flying landed the aircraft and began decelerating with breaks and thrust reversers. Just before transferring pedal controls to the Captain; Pilot Flying noted the breaks started working poorly. After Captain had control of aircraft; a number of hydraulic fail messages appeared on the EICAS. Captain was unable to steer and struggled to slow for a few seconds; but hydraulics kicked back on and we were able to taxi to the gate with no further issues. This hydraulic issue had also occurred on the previous flight. Maintenance had defered the automatic electronic hydraulic pump position. We were told to take off and land with the electronic hydraulic switch to on; which was completed; but this did not change the outcome after landing in ZZZ1.

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.