Narrative:

This is my second rotation off oe; so I am still getting used to this aircraft. I am very familiar with the local procedures in dca; including the operation of military helicopters along the river. Non standard separation over the river seems to be the norm for dca for some reason. I have not encountered this type of operation at any other us airport. We were approaching dca from over iad on the finks arrival. I was the PF. We had a moderate tailwind component in the descent which increased the workload to prepare for the river visual 19 approach. As anyone who has flown this approach before can attest; it is one of the most challenging approaches in the country. It takes a high level of concentration. That said; we were fully configured; stabilized and on speed at flaps 40 before 1000 ft AGL (vref=127K). As we rounded the corner over roosevelt island (to the left; approximately 500-700 ft); we received a TCAS TA. Tower reported 2 helicopters along the river as we received 2 more TA's. We had the helicopters' lights in sight at all times; and because of my familiarity with dca; I elected to continue to land. I felt confident that we would stay clear of the traffic; although it seemed closer than normal. The rest of the landing went normally. Only after I had a while to let what happened sink in did I realize how close the helicopters had been. I was looking at points of light; and maneuvering to avoid them; but I couldn't see the actual aircraft. In discussing it with the first officer later; he reported that we came about 200 ft and 0.2 mile at the closest point. I was looking through the HUD and not at the TCAS display since I was focused on making the turn to final. I failed to realize at the time that the TCAS RA feature was inhibited due to our low altitude. In retrospect; I believe that we would have certainly received an RA. If I were faced with this situation again; I would perform an go around. But I have to question the wisdom of dca tower letting helicopters fly in the approach path of one of the country's highest profile airports; particularly on an approach as challenging as this one. Note: it is common practice to hug the left bank of the river for this approach; because you can make the turn to final at a slightly higher altitude while remaining on profile for touchdown in the TDZ (it's not a long runway).

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Original NASA ASRS Text

Title: B737 ON VISUAL TO DCA RWY 19 EXPERIENCED TCAS TA WITH ISSUED VFR HELI TFC.

Narrative: THIS IS MY SECOND ROTATION OFF OE; SO I AM STILL GETTING USED TO THIS ACFT. I AM VERY FAMILIAR WITH THE LOCAL PROCS IN DCA; INCLUDING THE OP OF MIL HELIS ALONG THE RIVER. NON STANDARD SEPARATION OVER THE RIVER SEEMS TO BE THE NORM FOR DCA FOR SOME REASON. I HAVE NOT ENCOUNTERED THIS TYPE OF OP AT ANY OTHER US AIRPORT. WE WERE APPROACHING DCA FROM OVER IAD ON THE FINKS ARRIVAL. I WAS THE PF. WE HAD A MODERATE TAILWIND COMPONENT IN THE DSCNT WHICH INCREASED THE WORKLOAD TO PREPARE FOR THE RIVER VISUAL 19 APCH. AS ANYONE WHO HAS FLOWN THIS APCH BEFORE CAN ATTEST; IT IS ONE OF THE MOST CHALLENGING APPROACHES IN THE COUNTRY. IT TAKES A HIGH LEVEL OF CONCENTRATION. THAT SAID; WE WERE FULLY CONFIGURED; STABILIZED AND ON SPEED AT FLAPS 40 BEFORE 1000 FT AGL (VREF=127K). AS WE ROUNDED THE CORNER OVER ROOSEVELT ISLAND (TO THE L; APPROX 500-700 FT); WE RECEIVED A TCAS TA. TWR REPORTED 2 HELIS ALONG THE RIVER AS WE RECEIVED 2 MORE TA'S. WE HAD THE HELIS' LIGHTS IN SIGHT AT ALL TIMES; AND BECAUSE OF MY FAMILIARITY WITH DCA; I ELECTED TO CONTINUE TO LAND. I FELT CONFIDENT THAT WE WOULD STAY CLEAR OF THE TFC; ALTHOUGH IT SEEMED CLOSER THAN NORMAL. THE REST OF THE LNDG WENT NORMALLY. ONLY AFTER I HAD A WHILE TO LET WHAT HAPPENED SINK IN DID I REALIZE HOW CLOSE THE HELIS HAD BEEN. I WAS LOOKING AT POINTS OF LIGHT; AND MANEUVERING TO AVOID THEM; BUT I COULDN'T SEE THE ACTUAL ACFT. IN DISCUSSING IT WITH THE FO LATER; HE REPORTED THAT WE CAME ABOUT 200 FT AND 0.2 MILE AT THE CLOSEST POINT. I WAS LOOKING THROUGH THE HUD AND NOT AT THE TCAS DISPLAY SINCE I WAS FOCUSED ON MAKING THE TURN TO FINAL. I FAILED TO REALIZE AT THE TIME THAT THE TCAS RA FEATURE WAS INHIBITED DUE TO OUR LOW ALT. IN RETROSPECT; I BELIEVE THAT WE WOULD HAVE CERTAINLY RECEIVED AN RA. IF I WERE FACED WITH THIS SITUATION AGAIN; I WOULD PERFORM AN GAR. BUT I HAVE TO QUESTION THE WISDOM OF DCA TWR LETTING HELIS FLY IN THE APCH PATH OF ONE OF THE COUNTRY'S HIGHEST PROFILE ARPTS; PARTICULARLY ON AN APCH AS CHALLENGING AS THIS ONE. NOTE: IT IS COMMON PRACTICE TO HUG THE LEFT BANK OF THE RIVER FOR THIS APCH; BECAUSE YOU CAN MAKE THE TURN TO FINAL AT A SLIGHTLY HIGHER ALT WHILE REMAINING ON PROFILE FOR TOUCHDOWN IN THE TDZ (IT'S NOT A LONG RUNWAY).

Data retrieved from NASA's ASRS site as of January 2009 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.