EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Troubleshooting; Human-Machine Interface; Distraction
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Aircraft
This is not the first time this has happened. We had a lateral deviation [prior to this event] and filed an [ASRS Report]. Fortunately this happened at cruise. FMS (Flight Management) # 2 dropped offline during cruise. Messages on the FMS included: Single Operation; flight plan drops off; Independent Mode; ACARS (Aircraft Communications Addressing and Reporting System) not INIT; ACARS does not work on both FMS's; Lateral Mode is also lost on FMS # 2.On this particular flight there was no deviations but I'm filling out this [ASRS Report] to bring attention to all concerned that this is becoming a problem with FMS # 2 just dropping offline for no apparent reason. This has become more frequent since updating a software on the FMS which now requires us to put in the landing airport; OAT (Outside Air Temperature) and Altimeter setting to get landing aero data.Look into the software update to the FMS to find out what is causing the FMS to go into single mode and especially why the flight plan drops off. A similar incident happen again [recently] and I will be filling out another report.
EMB-145 Captain reported a lateral course deviation after their FMS dropped off line.