Narrative:

I contacted bwi approach for landing approximately 20 NM west of bwi. The frequency was extremely congested and it took several calls before contact was made. I was given vectors north of bwi in order to line up for landing. There was some problem on the controller's part understanding our type and call sign. After routing me north of the airport, they vectored me for landing, although I did not note any runway assignment or mention to 'expect' a specific runway. They called my 'base' but without assigning a runway for 3 closely aligned runways. Another aircraft was on a practice approach to runway 33R. The traffic was called and I searched and I believe we idented and called the aircraft 'in sight' (with the workload the exact timing of this is uncertain in my memory). I was told I would precede the aircraft for landing and to keep my speed up and was vectored for a base. I still had not, to my belief, received a runway assignment or clearance for landing. I was then handed off to the tower and changed to the tower frequency. I was unable to contact the tower in a timely way because the tower was chatting to another aircraft about a party they had recently had. We had still not received a runway assignment or clearance to land. During this time, I was focusing on which runway to line up on in the dusk. I believe I noted the other aircraft on approach against the ground lights. During this time, I was attempting to line up with the airport, configure the aircraft for landing, and trying to get a break in the radio chat about the party. I turned and saw the other aircraft rapidly approaching from my left and we passed extremely close. I finally was able to contact the tower and ask for clearance to land. It took several calls to receive the clearance which included a runway. By that time, I was unable to land due to altitude and alignment and opted to go around. I believe the following facts were significant contributions to the near midair collision: poor spacing of the aircraft on vectors for arrival. The congestion on the frequency made worse by a long discussion by the tower of the party with an aircraft. Failure to maintain proper visual separation by both VFR aircraft due to misjudging of distance or possible misident of the traffic against ground lights at dusk.

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Original NASA ASRS Text

Title: NMAC OCCURS BTWN A GA ACFT AND A DIAMOND DA40 WHEN THERE IS A RWY ASSIGNMENT MIX-UP FOR SEVERAL ACFT ON APCH TO BWI, MD.

Narrative: I CONTACTED BWI APCH FOR LNDG APPROX 20 NM W OF BWI. THE FREQ WAS EXTREMELY CONGESTED AND IT TOOK SEVERAL CALLS BEFORE CONTACT WAS MADE. I WAS GIVEN VECTORS N OF BWI IN ORDER TO LINE UP FOR LNDG. THERE WAS SOME PROB ON THE CTLR'S PART UNDERSTANDING OUR TYPE AND CALL SIGN. AFTER ROUTING ME N OF THE ARPT, THEY VECTORED ME FOR LNDG, ALTHOUGH I DID NOT NOTE ANY RWY ASSIGNMENT OR MENTION TO 'EXPECT' A SPECIFIC RWY. THEY CALLED MY 'BASE' BUT WITHOUT ASSIGNING A RWY FOR 3 CLOSELY ALIGNED RWYS. ANOTHER ACFT WAS ON A PRACTICE APCH TO RWY 33R. THE TFC WAS CALLED AND I SEARCHED AND I BELIEVE WE IDENTED AND CALLED THE ACFT 'IN SIGHT' (WITH THE WORKLOAD THE EXACT TIMING OF THIS IS UNCERTAIN IN MY MEMORY). I WAS TOLD I WOULD PRECEDE THE ACFT FOR LNDG AND TO KEEP MY SPD UP AND WAS VECTORED FOR A BASE. I STILL HAD NOT, TO MY BELIEF, RECEIVED A RWY ASSIGNMENT OR CLRNC FOR LNDG. I WAS THEN HANDED OFF TO THE TWR AND CHANGED TO THE TWR FREQ. I WAS UNABLE TO CONTACT THE TWR IN A TIMELY WAY BECAUSE THE TWR WAS CHATTING TO ANOTHER ACFT ABOUT A PARTY THEY HAD RECENTLY HAD. WE HAD STILL NOT RECEIVED A RWY ASSIGNMENT OR CLRNC TO LAND. DURING THIS TIME, I WAS FOCUSING ON WHICH RWY TO LINE UP ON IN THE DUSK. I BELIEVE I NOTED THE OTHER ACFT ON APCH AGAINST THE GND LIGHTS. DURING THIS TIME, I WAS ATTEMPTING TO LINE UP WITH THE ARPT, CONFIGURE THE ACFT FOR LNDG, AND TRYING TO GET A BREAK IN THE RADIO CHAT ABOUT THE PARTY. I TURNED AND SAW THE OTHER ACFT RAPIDLY APCHING FROM MY L AND WE PASSED EXTREMELY CLOSE. I FINALLY WAS ABLE TO CONTACT THE TWR AND ASK FOR CLRNC TO LAND. IT TOOK SEVERAL CALLS TO RECEIVE THE CLRNC WHICH INCLUDED A RWY. BY THAT TIME, I WAS UNABLE TO LAND DUE TO ALT AND ALIGNMENT AND OPTED TO GO AROUND. I BELIEVE THE FOLLOWING FACTS WERE SIGNIFICANT CONTRIBUTIONS TO THE NMAC: POOR SPACING OF THE ACFT ON VECTORS FOR ARR. THE CONGESTION ON THE FREQ MADE WORSE BY A LONG DISCUSSION BY THE TWR OF THE PARTY WITH AN ACFT. FAILURE TO MAINTAIN PROPER VISUAL SEPARATION BY BOTH VFR ACFT DUE TO MISJUDGING OF DISTANCE OR POSSIBLE MISIDENT OF THE TFC AGAINST GND LIGHTS AT DUSK.

Data retrieved from NASA's ASRS site as of July 2007 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.