Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness; Workload
Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control
Human Factors; Weather
We were being vectored around weather to final approach for LDA Z Runway 19 into DCA. We were passed FAF (Final Approach Fix) descending to MDA altitude prior to our missed approach fix ZAXEB. Weather was being reported above minimums at the time we were established; and we were getting constant reports by ATC regarding rapidly changing weather due to heavy weather around Washington. On descent prior to the missed approach point; we got an aural 'caution obstacle' (the bridge) around 1;000 feet. At that point we corrected the situation immediately by leveling off and I had visual with the ground. Rest of the flight and landing continued uneventful.I think that the aural was triggered because of the rate of descent around the fix WEVPU which we didn't manually load; and at that moment dealing with high saturation workload; plus the moderate turbulence and weather that we had throughout the whole approach saturated us and we missed that fix and the rate of decent we had using vertical speed mode; which was probably around 1;100 feet and as soon as the aural came; we immediately took action; corrected the rate of decent and started to level off; which discontinued the aural immediately. I did not executed a go-around at that precise moment because I immediately had visual on terrain outside; plus the action taken fixed the problem immediately; and the flight characteristics were stable; without the need to make any evasive action. I think adding that WEVPU fix; or having a lower rate of descent will prevent this problem from repeating.Pilots talked about this approach when briefed while enroute from ZZZ; and we talked about not manually loading; adding the fix between FAF and MAP; due to the fact that we expected workload saturation to be high due to constant reports of weather; minimums for landing; visibility and the heavy storms around the area; and decided to monitor the altitude and make corrections for our rate of descent by monitoring distance from the set fixes and make corrections as needed. On final approach we were under moderate rain and continuous moderate turbulence; once past FAF we started our descent to MDA altitude set to 800 feet around 1;000 feet we got the aural 'caution obstacle;' at that point I had visual with outside terrain and decreased the rate of descent on flight panel since FO pilot flying was very busy trying to maintain controlled airspeed due to the turbulence; and simultaneously FO started to level off which subsequently came around 900 feet. I did not lost visual of outside terrain at any point when this happened (I was being eyes outside eyes inside and scanning airspeed and making changes in flight control panel for landing configuration and to maintain everything within limits. We got a visual on the runway prior to our MAP and were established for normal landing without any issues in regards with flight controls; airspeed; configuration.
CRJ-700 Captain reported getting an aural caution warning for an obstacle during descent on approach to DCA airport which resulted in evasive action.