EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; Flight Crew Overrode Automation; Flight Crew Regained Aircraft Control; Flight Crew Returned To Clearance; General Maintenance Action
Aircraft
During departure and approach phases; FMS switched to ROLL-GA (Go Around) modes without pilot command. On takeoff from ZZZ; performing the ZZZZZ1 departure from runway XX in HDG (heading) mode; PF (Pilot Flying) called for and PM (Pilot Monitoring) confirmed PITCH mode at acceleration altitude. PM also selected and confirmed E CLB (climb); as had been briefed prior to takeoff. While in the turn to heading XXX to intercept ZZZ RXXX to ZZZZZ; the FMS spontaneously and uncommanded switched to ROLL-GA modes.PF was hand flying; recognized the mode switch; and was able to disregard the flight director's direction. PM re-sequenced FMS for ZZZ - ZZZZZ leg and selected CLB thrust and HDG; PITCH modes with LNAV selected for course interception. After course intercept; autopilot was engaged. FMS performed nominally until ZZZ1 terminal area. Cleared from base leg for descent to 7000'; given vector to intercept localizer for ILS XXR; and cleared for visual approach; PF selected VS mode to begin descent and assigned heading in HDG mode with LNAV pre-selected for intercept. Autopilot was engaged. Again; spontaneously and uncommanded; FMS switched to ROLL-GA modes. Autopilot initiated climb. PF recognized the malfunction; switched off the autopilot; arrested climb; re-trimmed; and hand flew approach to landing. PM selected CRUISE thrust. (GA mode climbed aircraft from about 7400' MSL to about 7600' MSL before recovery and pilot resumption of descent.) PM attempted several times to re-sequence approach in FMS; FMS kept returning to ROLL-GA mode. Additionally; attempts to turn off distracting Flight Director and use raw green needle LOC/GS data for visual approach were unsuccessful. PF landed visually. After arrival at gate and aircraft shutdown; malfunction was entered into maintenance logbook and Maintenance control was contacted.
EMB XRJ-145 Captain reported auto flight system malfunctioned during departure and arrival phase by uncommanded reversion to Roll-Go Around mode.