Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Communication Breakdown
ATC Issue All Types; Conflict NMAC
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Human Factors
[Our flight] into DCA was in a NMAC. We were supposed to circle from the visual Runway 1 to instead land on 33. We followed the [company] station bulletin procedures exactly as planned and came within very close contact of another aircraft. This occurred about 400 feet off the ground to the point where the pilot monitoring had to take the controls to make a correction in order to prevent it from becoming a midair collision. After there was action taken to make a correction from the close call; we were then informed by DCA tower of close traffic although at that point it would have been too late. I have flown with people who for the purpose of having a better chance of a stabilized approach would have had a wider circle to land procedure which I'm sure would have almost definitely ended in the collision of two aircraft over the turn to final for 33 in DCA. There was an extreme lack of communication between DCA Tower to [our flight] or DCA Tower to the associated helicopter who did not ever pop up on TCAS which I'm assuming is due to a lack of an operating transponder. No TCAS RA was associated with this event.This occurred due to an extreme lack of communication between DCA Tower and [our flight] or DCA Tower and the associated helicopter. Otherwise the other reason this may have happened is because of an unclear idea of where aircraft should be located during Runway 33 circle to land operations. I believe I was on track with what the [company] guidelines are for that particular procedure but there is a possibility that the other traffic operating around that area may not be aware of where exactly we are located or maybe they don't have a specific guideline to keep the arriving traffic separated from the low flying helicopters.
[Report narrative contained no additional information.]
A CRJ-200 flight crew reported a NMAC with a helicopter on approach to Runway 33 at DCA. The crew stated the traffic call from Tower came too late to be effective.