Narrative:

Dulles approach control was vectoring us for final to runway 1L at night. There were two lines of traffic landing runway 1L and 1R and a long stream of hits on the TCAS. Approach vectored us from the SHNON2 arrival to a left base approximately abeam fazer to the west of about 13 miles out at 4000 ft. On base; approach called out our traffic to follow was a saab at 10 o'clock. There were three bogies in that area and being at night; it was impossible to tell anything about the various aircraft and we said so. At that position; it was not even possible to be sure any of the three in just that one area were on approach into dulles. In all we had about 10 aircraft on TCAS within 10 miles at various clock positions; all to the east of us. Approach tried a second time to direct us to take a visual behind the saab even though we communicated we could not be certain which one was the saab. For a third time; approach tried to get us to take the visual behind the saab saying: 'everyone else does it.' now we could not tell which airplane was the one to follow (although the one I saw as most likely being the saab ended up behind the aircraft we followed in). At no time could I really tell what size it was or exactly how far away it was. I only had the flashing white and red lights to judge distance/size/speed by at that time of night and distances; size and closure rates can be deceiving. Furthermore; even after getting the 'right' airplane; that airplane could have been a piper or a regional jet for all we knew. (It could have been a volvo with wings and we wouldn't have been able to identification it!) I broke in and asked for vectors to the ILS. Approach gave us a left turn to the northeast and clearance to capture the localizer. They asked us to slow to approach speed more the 11 miles out. We complied slowing to 135 KTS. On the localizer; they cleared us for the ILS from 4000 ft at around biggz about 10 miles out. On final; it became apparent on the basis of our TCAS that we were gaining on the traffic ahead of us. I could not 'see' the closure rate even though I could clearly see his lights. I asked tower (having been switched on final) for our overtake. Tower said it was 30 KTS. The distance between us and the saab even at our approach speed lessened from around 4 miles to just less than 2 and 1/2. We were worried about spacing; we didn't have enough gas to do a full go-around to the holding pattern and another approach with another 15 mile final and remain above reserve. We planned on doing a 'closed' pattern if necessary. Getting the overtake out on the radio had the benefit of informing the saab of our dilemma. The saab landed with us around 800 ft on final. Tower asked them to expedite their exit from the runway. At about 400 ft on final; the saab cleared runway 1L and we were able to land safely with the runway being clear. We felt the controlling from dulles was less than satisfactory. They did not compensate for speed differences and did not build in enough room for the diverse aircraft they handle. Approach relied on the pilot to take visuals at night on the basis of identifying aircraft on only their strobes and anti-collision light for safe separation. I thought everyone learned a lesson from their mothers that 'just because everyone is doing it' is not a good enough reason to so something...hopefully; dulles approach will learn that lesson before any negative consequences accrue to the people in the airplanes under their control.

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Original NASA ASRS Text

Title: An air carrier Captain reported what he believes was unsatisfactory traffic handling by Approach Control.

Narrative: Dulles Approach Control was vectoring us for final to Runway 1L at night. There were two lines of traffic landing Runway 1L and 1R and a long stream of hits on the TCAS. Approach vectored us from the SHNON2 arrival to a left base approximately abeam FAZER to the west of about 13 miles out at 4000 FT. On base; approach called out our traffic to follow was a SAAB at 10 o'clock. There were three bogies in that area and being at night; it was impossible to tell anything about the various aircraft and we said so. At that position; it was not even possible to be sure any of the three in just that one area were on approach into Dulles. In all we had about 10 aircraft on TCAS within 10 miles at various clock positions; all to the east of us. Approach tried a second time to direct us to take a visual behind the SAAB even though we communicated we could not be certain which one was the SAAB. For a third time; approach tried to get us to take the visual behind the SAAB saying: 'Everyone else does it.' Now we could not tell which airplane was the one to follow (although the one I saw as most likely being the SAAB ended up behind the aircraft we followed in). At no time could I really tell what size it was or exactly how far away it was. I only had the flashing white and red lights to judge distance/size/speed by at that time of night and distances; size and closure rates can be deceiving. Furthermore; even after getting the 'right' airplane; that airplane could have been a Piper or a regional jet for all we knew. (It could have been a Volvo with wings and we wouldn't have been able to ID it!) I broke in and asked for vectors to the ILS. Approach gave us a left turn to the northeast and clearance to capture the localizer. They asked us to slow to approach speed more the 11 miles out. We complied slowing to 135 KTS. On the localizer; they cleared us for the ILS from 4000 FT at around BIGGZ about 10 miles out. On final; it became apparent on the basis of our TCAS that we were gaining on the traffic ahead of us. I could not 'see' the closure rate even though I could clearly see his lights. I asked Tower (having been switched on final) for our overtake. Tower said it was 30 KTS. The distance between us and the SAAB even at our approach speed lessened from around 4 miles to just less than 2 and 1/2. We were worried about spacing; we didn't have enough gas to do a full go-around to the holding pattern and another approach with another 15 mile final and remain above reserve. We planned on doing a 'closed' pattern if necessary. Getting the overtake out on the radio had the benefit of informing the SAAB of our dilemma. The SAAB landed with us around 800 FT on final. Tower asked them to expedite their exit from the runway. At about 400 FT on final; the SAAB cleared runway 1L and we were able to land safely with the runway being clear. We felt the controlling from Dulles was less than satisfactory. They did not compensate for speed differences and did not build in enough room for the diverse aircraft they handle. Approach relied on the pilot to take visuals at night on the basis of identifying aircraft on only their strobes and anti-collision light for safe separation. I thought everyone learned a lesson from their mothers that 'Just because everyone is doing it' is not a good enough reason to so something...Hopefully; Dulles Approach will learn that lesson before any negative consequences accrue to the people in the airplanes under their control.

Data retrieved from NASA's ASRS site as of April 2012 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.