Narrative:

As we were descending on a STAR arrival. We were [cleared to cross the next fix] at 10;000 feet and 250 knots. We were just preparing to begin the descent when suddenly I heard a noise like a cabin door opening inflight followed by what I recognized as the RAT beginning to spin up. This was followed immediately by an EICAS message of electrical emergency and multiple secondary messages/alerts. I called for the electrical emergency QRH procedure. ATC notified us ZZZ1 was 12 miles ahead. Considering the emergency; weather and the shorter runway [at our destination] we elected to divert into ZZZ1. While ATC was vectoring us for the approach the first officer continued with the QRH procedure while setting up and briefing the approach. I notified the flight attendants and passengers as to our emergency and [that we] were diverting into ZZZ1. After successfully starting the APU; partial power and some systems were re-established. We broke out of the overcast layer approximately 1500 feet afe and were able to complete the approach visually. I noticed and mentioned that we were receiving localizer information but no glide slope information; and ATC confirmed glide slope was functioning normally. Landing was accomplished without further incident and taxi to gate was normal; except when we got to the gate the landing lights would not extinguish even though the switches were in the off position. Passengers were deplaned and aircraft was shut down. Even with ground power attached; we could not gain control of landing and emergency lights in cabin and kept receiving spurious EICAS alerts. All of these items kept re-occurring until aircraft was completely shut down.[although the cause was not evident; the] previous crew reported that even while flying through what they perceived as icing condition; no EICAS icing alert messages were generated. We [had] experienced the same thing. And while airborne; we checked the anti-ice system mfd page. Although the anti-ice system was never activated; we noticed the wing temperature indication go from 3 celsius to 36 celsius then back to 3 celsius all the while indicating that the anti-ice valve to the wings was closed.

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Original NASA ASRS Text

Title: While descending to their destination the flight crew of an EMB-190 experienced a massive loss of electrical systems to the extent that the RAT automatically deployed. They conducted QRH checklists and opted to divert to a nearby airport with longer runways than were available at their destination. They landed safely after having regained some systems via the APU generator. Previous reports of anti-icing system failure to provide and EICAS icing alerts and inappropriate operation of wing anti-ice suggested a path of investigation for Maintenance.

Narrative: As we were descending on a STAR arrival. We were [cleared to cross the next fix] at 10;000 feet and 250 knots. We were just preparing to begin the descent when suddenly I heard a noise like a cabin door opening inflight followed by what I recognized as the RAT beginning to spin up. This was followed immediately by an EICAS message of electrical emergency and multiple secondary messages/alerts. I called for the electrical emergency QRH procedure. ATC notified us ZZZ1 was 12 miles ahead. Considering the emergency; weather and the shorter runway [at our destination] we elected to divert into ZZZ1. While ATC was vectoring us for the approach the First Officer continued with the QRH procedure while setting up and briefing the approach. I notified the flight attendants and passengers as to our emergency and [that we] were diverting into ZZZ1. After successfully starting the APU; partial power and some systems were re-established. We broke out of the overcast layer approximately 1500 feet AFE and were able to complete the approach visually. I noticed and mentioned that we were receiving localizer information but no glide slope information; and ATC confirmed glide slope was functioning normally. Landing was accomplished without further incident and taxi to gate was normal; except when we got to the gate the landing lights would not extinguish even though the switches were in the off position. Passengers were deplaned and aircraft was shut down. Even with ground power attached; we could not gain control of landing and emergency lights in cabin and kept receiving spurious EICAS alerts. All of these items kept re-occurring until aircraft was completely shut down.[Although the cause was not evident; the] previous crew reported that even while flying through what they perceived as icing condition; no EICAS icing alert messages were generated. We [had] experienced the same thing. And while airborne; we checked the anti-ice system MFD page. Although the anti-ice system was never activated; we noticed the wing temperature indication go from 3 Celsius to 36 Celsius then back to 3 Celsius all the while indicating that the anti-ice valve to the wings was closed.

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.