Narrative:

I was working in the tower with all positions combined. We were arriving and departing runway 24. East radar brought two airplanes to the final approach course; a dash 8 and a CRJ2; at the same time and had the dash 8 cut in front of the CRJ2. The dash 8 was supposed to be providing visual separation with the CRJ2 but there is no way that he could do that as the CRJ2 was behind him. East radar called up and asked if I 'had visual on the aircraft.' I replied 'I see them' because there was no way that it was possible for me to provide visual separation with the two as there was no other approved separation existing. I explicitly did not say that I could provide visual separation. My guess is that they were separated by less than one mile. I cleared the dash 8 to land; but did not tell him anything about minimum time on the runway because I had already planned to send the CRJ2 around. Somehow the dash 8 touched down and turned off at taxiway alpha before the CRJ2 got to an unsafe altitude for a go-around so I cleared him to land as well. Runway separation turned out to not be an issue. However; in my opinion this was an extremely unsafe operation. I assumed that the radar controller had done everything required of him until I listened to the tapes later and found out that things were in fact far worse than I had originally thought. More practice sequencing from the approach controller and additional instruction on how to properly apply visual separation.

Related reports:

Google
 

Original NASA ASRS Text

Title: Tower Controller described a developing separation problem on final. Controller noted the TRACON Controller's application of 'Visual Separation' as questionable.

Narrative: I was working in the Tower with all positions combined. We were arriving and departing Runway 24. East RADAR brought two airplanes to the final approach course; a Dash 8 and a CRJ2; at the same time and had the Dash 8 cut in front of the CRJ2. The Dash 8 was supposed to be providing visual separation with the CRJ2 but there is no way that he could do that as the CRJ2 was behind him. East RADAR called up and asked if I 'had visual on the aircraft.' I replied 'I see them' because there was no way that it was possible for me to provide visual separation with the two as there was no other approved separation existing. I explicitly did not say that I could provide visual separation. My guess is that they were separated by less than one mile. I cleared the Dash 8 to land; but did not tell him anything about minimum time on the runway because I had already planned to send the CRJ2 around. Somehow the Dash 8 touched down and turned off at Taxiway Alpha before the CRJ2 got to an unsafe altitude for a go-around so I cleared him to land as well. Runway separation turned out to not be an issue. However; in my opinion this was an extremely unsafe operation. I assumed that the RADAR Controller had done everything required of him until I listened to the tapes later and found out that things were in fact far worse than I had originally thought. More practice sequencing from the Approach Controller and additional instruction on how to properly apply visual separation.

Data retrieved from NASA's ASRS site as of July 2013 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.