Narrative:

I was working graco and bwifs combined; which is routine as we were on late night operations. I had a dash 8 inbound from the east; and then took a hand off on a hawker jet from the northeast. Both were inbound for 33R at bwi. I descended the hawker jet to 3;000 ft; to make him number one in my sequence. He was direct bwi. I kept the dash 8 at 6;000 ft for awhile; letting the jet get underneath. I also issued the dash 8 a ten degree left turn to build in a little more spacing. The hawker jet appeared to slow at one point; I asked him his airspeed; he said he had slowed to 200 KTS; and I asked him to keep the speed up as I was making him number 1. At about 10 miles east of the airport the hawker reported the airport in sight; and I cleared him for the visual and switched him to the tower. The dash 8 was on a nice parallel heading to follow. I kept vertical separation until the dash 8 reported the hawker in sight; then I told him to follow the hawker and cleared him for the visual approach to 33R. At this point; the hawker was a few miles from bwi and then turned due south. Normally they'll set themselves up with a good angle to intercept once cleared; but the pilot of the hawker seemed to wait until the last minute. The jet was a few miles northwest of the west bound dash 8; and the dash 8; who had him in sight; was to be following him; and continued to descend. I had told the dash 8 the hawker was southbound apparently setting himself up to join further south; and I thought he was finally turning inbound. The hawker was not turning toward the runway; he was flying totally opposite of bwi. I called the tower to find out what the hawker was doing. The tower seemed to be issuing some visual separation of their own; and didn't seem to know what this guy was doing either. I tried to keep the dash 8 pilot updated. I believe he had an RA and started to climb. The jet was southbound for some reason; and the dash 8 was westbound following the aircraft that was going away from the airport. I also had a B737 inbound from the south. I knew he wasn't going to be able to continue to grafe and join; so I issued him a 330 heading and explained what was going on. The dash 8 then climbed to 3;300; then 3;400. I told him I could make him number 1 if he wanted to turn inbound; but he asked to make a turn towards the south. I approved it; but told him he needed to get down and maintain 3;000. I had kept the B737 at 4;000 just in case this happened. The dash 8 was very slow to get down; I issued traffic to the B737; he immediately called him in sight and I issued visual. I didn't lose separation; but thought it should be explained. I had called the tower about making dash 8 number 1 now as this hawker was doing his own thing. By the time the dash 8 rolled southeast; it made sense to have the hawker go first as he had finally turned inbound. The dash 8 was established eastbound at 3;000 still had the inbound hawker insight and followed him in visually. The B737 needed to make a left 360 to land the left side; and did so. Afterwards I called the tower to ask what the pilot of the hawker was thinking; if he said anything; or just something to make sense of what he was doing; and the local controller said the pilot just 'screwed up'. Separation was never lost as there was visual being applied the whole time; but I still found it to be very dangerous. For the hawker pilot to make a south turn like that was very odd. He wasn't even setting himself up for a standard turn on. I was also surprised that the dash 8 continued to descend like he did seeing the hawker on a converging course. Had the dash 8 never called the hawker insight initially; I would have just vectored him to follow the hawker; but once he had him in sight; I let him follow the hawker visually. I suppose in the future I should not ever allow that; but then that defeats the purpose of allowing pilots to follow one another inbound to an airport. Recommendation; not allow visual separation? I could vector everyone to the small runway like I do the big jets on the left side. I could also always give a lot more spacing in case a pilot does something he shouldn't. I think both are a little much; but perhaps the right technique.

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Original NASA ASRS Text

Title: PCT Controller described a very confusing visual approach to BWI when the lead aircraft made multiple unexpected turns after being cleared and transferred to the Tower. Thus; making instructions to the following aircraft very difficult.

Narrative: I was working GRACO and BWIFS combined; which is routine as we were on late night operations. I had a Dash 8 inbound from the east; and then took a hand off on a Hawker jet from the northeast. Both were inbound for 33R at BWI. I descended the Hawker jet to 3;000 FT; to make him number one in my sequence. He was direct BWI. I kept the Dash 8 at 6;000 FT for awhile; letting the jet get underneath. I also issued the Dash 8 a ten degree left turn to build in a little more spacing. The Hawker jet appeared to slow at one point; I asked him his airspeed; he said he had slowed to 200 KTS; and I asked him to keep the speed up as I was making him number 1. At about 10 miles east of the airport the Hawker reported the airport in sight; and I cleared him for the visual and switched him to the Tower. The Dash 8 was on a nice parallel heading to follow. I kept vertical separation until the Dash 8 reported the Hawker in sight; then I told him to follow the Hawker and cleared him for the visual approach to 33R. At this point; the Hawker was a few miles from BWI and then turned due south. Normally they'll set themselves up with a good angle to intercept once cleared; but the pilot of the Hawker seemed to wait until the last minute. The jet was a few miles northwest of the west bound Dash 8; and the Dash 8; who had him in sight; was to be following him; and continued to descend. I had told the Dash 8 the Hawker was southbound apparently setting himself up to join further south; and I thought he was finally turning inbound. The Hawker was not turning toward the runway; he was flying totally opposite of BWI. I called the Tower to find out what the Hawker was doing. The Tower seemed to be issuing some visual separation of their own; and didn't seem to know what this guy was doing either. I tried to keep the Dash 8 pilot updated. I believe he had an RA and started to climb. The jet was southbound for some reason; and the Dash 8 was westbound following the aircraft that was going away from the airport. I also had a B737 inbound from the south. I knew he wasn't going to be able to continue to GRAFE and join; so I issued him a 330 heading and explained what was going on. The Dash 8 then climbed to 3;300; then 3;400. I told him I could make him number 1 if he wanted to turn inbound; but he asked to make a turn towards the south. I approved it; but told him he needed to get down and maintain 3;000. I had kept the B737 at 4;000 just in case this happened. The Dash 8 was very slow to get down; I issued traffic to the B737; he immediately called him in sight and I issued visual. I didn't lose separation; but thought it should be explained. I had called the Tower about making Dash 8 number 1 now as this Hawker was doing his own thing. By the time the Dash 8 rolled southeast; it made sense to have the Hawker go first as he had finally turned inbound. The Dash 8 was established eastbound at 3;000 still had the inbound Hawker insight and followed him in visually. The B737 needed to make a left 360 to land the left side; and did so. Afterwards I called the Tower to ask what the pilot of the Hawker was thinking; if he said anything; or just something to make sense of what he was doing; and the Local Controller said the pilot just 'screwed up'. Separation was never lost as there was visual being applied the whole time; but I still found it to be very dangerous. For the Hawker pilot to make a south turn like that was very odd. He wasn't even setting himself up for a standard turn on. I was also surprised that the Dash 8 continued to descend like he did seeing the Hawker on a converging course. Had the Dash 8 never called the Hawker insight initially; I would have just vectored him to follow the Hawker; but once he had him in sight; I let him follow the Hawker visually. I suppose in the future I should not ever allow that; but then that defeats the purpose of allowing pilots to follow one another inbound to an airport. Recommendation; not allow visual separation? I could vector everyone to the small runway like I do the big jets on the left side. I could also always give a lot more spacing in case a pilot does something he shouldn't. I think both are a little much; but perhaps the right technique.

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.