EMB175 flight crew reported automation mismanagement resulted in a low altitude alert on a visual approach.
Synopsis
EMB175 flight crew reported automation mismanagement resulted in a low altitude alert on a visual approach.
Narrative
Low Altitude Alert Aircraft X from ZZZ2 to ZZZ1; was re-routed before push back to make a fuel stop in ZZZ; since we were weight restricted leaving ZZZ2. Since ZZZ2 was a special airport; the Captain being the PIC (Pilot in Command); landed there and took off from ZZZ2. Since the Captain flew the leg there; he offered to switch flight controls once we were in cruise so that I the SIC (Second in Command) could get some flying in too. We switched flight controls and radios at cruise; so the Captain became the Pilot Monitoring and I the FO (First Officer) became the Pilot Flying. Going into ZZZ we knew the winds would only allow us to land on Runway XX or Runway XY. Any other runway would exceed our 10 kts. tail wind limitation.When we were about 20 miles from the airport coming from the North; Approach Control was vectoring us for the visual for Runway XX. ZZZ only has a RNP approach for Runway XX and XY. We do not have a copy of either approach in our EFB and we also don't have it in our FMS. So; we were doing an actual Visual approach since we had nothing to back up the visual approach with. In ZZZ2 we briefed the visual for ZZZ and again in our decent into ZZZ. We noted the MSA off the ZZZ VOR and the traffic pattern altitude in ZZZ. The field elevation being 5355 ft. MSL making the traffic pattern 6900 ft MSL. We added three distance rings using the NAV FIX INFO function on the FMS to help with our descent planning and where we wanted to be on final and what altitudes we wanted to be at using a 3-degree decent.Approach control was vectoring us for a 45-degree right down wind entry for Runway XX. We were asked if we had the field in sight and we replied that we do; but that a scattered cloud might come in between us and the field and asked if we could keep getting vectors until we were clear of it. Approach lowered us to 7;000 ft and gave us a heading that would set us up for about a 45-degree entry abeam the thousand-ft. markers on Runway XX.Approach cleared us down to 7000 ft. and said that he couldn't give us anymore vectors and asked if we still had the field in sight. We did have the field in sight with no clouds being a factor. The phraseology was a little different from what the Captain was expecting to hear and he also missed the call sign. So he missed the radio call. I heard it and responded to Approach Control. Approach then came back on and cleared us for the visual and told us to switch over to Tower. The Captain repeated the radio call and switched over to Tower. As he switched over to Tower we were about 2 miles away and we turned to join down wind of Runway XX. Tower then cleared us to land.After that the Captain was asking me what Approach said on the call that he missed. After discussing the radio call we talked about when to turn final and talked about our altitudes that we were planning on being at on final. At this point we were flaps 2; speed 180. Being cleared to land; we set the altitude bug to 6400 ft. At this time the plane was still descending. The Captain said lets level off here until we turn base. The airspeed at this time was decreasing and dropped to about 160 kts. The Captain said check airspeed. The speed bug was at 180 and the auto throttles were at idle. So I turned off the autopilot and increased the throttles. We weren't sure at the time why the auto throttles were still trying to go to idle. The Captain said just turn them off and hand fly it. This was about 30 seconds after being abeam the thousand ft. markers so we started our turn to base leg.At this time Tower came on and said they are getting a low altitude alert and gave us the current altimeter setting. We corrected the altitude setting which was off by .02 Hg. We noticed at this time we were about 300 to 400 ft. low. We leveled off and got our airspeed back under control. We started a slight climb and then leveled off just under traffic pattern. We then did flaps 3 and landing gear down. We turned to intercept final andbugged V approach and flaps 5. We did the before landing checklist. As we joined final we were 3 red lights and 1 white light on the PAPI. We were stable and fully configured by 1000 ft. AGL. So we continued the approach; set the missed approach altitude and landed with no further incidents.After discussing why the auto throttles were doing that; we believe that we probably were still in FLCH when we put in 6400 ft. in the attitude bug. So the auto throttles were trying to get us to descend. With all that happening while we were turning base; we got a little flustered and descended lower than we should have. Luckily we were monitoring the situation and caught it before it got us into a worse situation. Also instead of waiting and trying to fix the automation we just turned off all the automation and flew the plane first. That saved us from getting into a worst situation.Some major factors that played a role in this situation was missing a radio call during a crucial time; unnecessarily worrying about what we were going to be doing when we landed (since this was a first time for both us having to do a fuel stop and not having a gate to go to); and not having anything to back up our visual approach. Looking back on it; the Captain probably should have done the visual approach since he had more experience doing visual approaches. This was a humbling learning experience.
Second reporter narrative
[Report narrative contained no additional information.]
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.