Narrative:

I was the pilot monitoring (pm) and the first officer was pilot flying (PF). We were cleared for the lda 19 approach into dca. The weather was showing scattered at 1;200 feet and we were direct fergi on the approach adhering to each step down fix. We broke out of the clouds approximately 1;300 MSL and clearly observed the river and airport; and continued to cross wevpu at 1;100 MSL and then fly the river.as we were crossing over wevpu; we received the gpsw caution terrain. I initially believed this was possibly a malfunction of the gpsw because we were VMC; we both observed the river in front of us; and there were no obstacles in are flight path. I stated to the PF that I don't see any obstacles or terrain. A second or two later we received a pull-up terrain and the PF discounted the autopilot and proceeded to fly more towards the center of the river. The gpsw warning then discontinued. Also during that time ATC advised us of a low altitude or a low terrain alert which we acknowledge and safely landed the aircraft.I have done the lda several times over the years; but just four or five times as captain. The view of the river and where we were; looked about what I have seen in the past. Other than; we were closer to the south side of the river at wevpu where the buildings are noted on the approach plate; which I believe initiated the gpsw. We probably should have been more towards the center of the river. Had we been in IMC conditions or observed an obstacle in front of us we would have immediately preformed an escape maneuver.after we landed; I then noted I had switched to the lda frequency; but had not switched over to green needed from white and also noted the pm was in white needles too. This approach seemed to happen faster than what I can recall. I was focused on the 0.2-mile callouts and forgot to switch over to green needles; as did the PF. I am not sure if that caused us to get closer to the south end of the river to trigger the gpsw. This is an approach that I will have to scrutinize to make sure both pilots are in green needles for this approach ;and to have the aircraft in the center of the river and not closer to the south end of the river where the buildings are as noted on the approach plate.

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Original NASA ASRS Text

Title: Air Carrier flight crew reported receiving two GPWS warnings; followed by a low altitude alert from ATC while on final approach.

Narrative: I was the Pilot Monitoring (PM) and the First Officer was Pilot Flying (PF). We were cleared for the LDA 19 approach into DCA. The Weather was showing Scattered at 1;200 feet and we were direct FERGI on the approach adhering to each step down fix. We broke out of the clouds approximately 1;300 MSL and clearly observed the river and airport; and continued to cross WEVPU at 1;100 MSL and then fly the river.As we were crossing over WEVPU; we received the GPSW caution terrain. I initially believed this was possibly a malfunction of the GPSW because we were VMC; we both observed the river in front of us; and there were no obstacles in are flight path. I stated to the PF that I don't see any obstacles or terrain. A second or two later we received a pull-up terrain and the PF discounted the autopilot and proceeded to fly more towards the center of the river. The GPSW warning then discontinued. Also during that time ATC advised us of a low altitude or a low terrain alert which we acknowledge and safely landed the aircraft.I have done the LDA several times over the years; but just four or five times as Captain. The view of the river and where we were; looked about what I have seen in the past. Other than; we were closer to the south side of the river at WEVPU where the buildings are noted on the approach plate; which I believe initiated the GPSW. We probably should have been more towards the center of the river. Had we been in IMC conditions or observed an obstacle in front of us we would have immediately preformed an escape maneuver.After we landed; I then noted I had switched to the LDA frequency; but had not switched over to green needed from white and also noted the PM was in white needles too. This approach seemed to happen faster than what I can recall. I was focused on the 0.2-mile callouts and forgot to switch over to green needles; as did the PF. I am not sure if that caused us to get closer to the south end of the river to trigger the GPSW. This is an approach that I will have to scrutinize to make sure both pilots are in green needles for this approach ;and to have the aircraft in the center of the river and not closer to the south end of the river where the buildings are as noted on the approach plate.

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.