EMB ERJ 190/195 ER/LR
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 40; Flight Crew Total 21000; Flight Crew Type 10000
Time Pressure; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
900 miles out of ZZZ; just past ZZZZZ. We received ATA Fail> AUNX MAU (Master Avionics Unit) 3A Fail. ADS 3 Fail. Spoiler Fault. FDR AFT Fail. Auto Config Trim FailAll nav indications on the FO (First Officer) side is gone. Flight director is gone. Auto throttle disengaged and auto pilot disengaged. We performed QRH for the AUNX (Annunciator Message). We found that we have lost systems and flight controls; i.e. multi-functional spoilers and speed brakes. In addition we were not for sure if we had lost OB brakes...no indication on the status page. This concerned us given; #2 OB locked up on validation flight. We made a crew decision to turn back for ZZZ. Once it was decided we were turning back; we proceeded off tracks; made a climb to proper altitude; and then intercepted track back to ZZZ. Notified ATC and Airline that we were returning as a [priority handling] aircraft.
Captain reported MAU3A failed in flight; causing the loss of numerous systems. Captain performed an air turn back a safe precautionary landing.