B737 Undifferentiated or Other Model
Air Traffic Control Fully Certified
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Human Factors; ATC Equipment / Nav Facility / Buildings
I gave a position relief briefing and was completing my overlap when the Controller that relieved me cleared a Learjet 45 for a visual approach to Runway 35 without having the proceeding B737 in sight. The B737 slowed to 130 KTS across the ground and the Learjet closed to approximately 3.6 miles behind the B737. Also; the Controller switched the Learjet late to the Tower. The Tower had no real opportunity to send the Lear around before the B737 crossed the landing threshold. I would have had the Lear report the B737 in sight to follow. I asked the Lear to report the B737 in sight when I turned the Lear base leg. This is the point when the relieving Controller assumed responsibility for the position. The Lear said he was looking. The relieving Controller did not ask the Lear a second time to report the B737 in sight. He just asked him to report the airport in sight. When the Lear reported the airport in sight the relieving Controller cleared him for a visual approach. Later the relieving Controller told me that I had a video map and that he was not use to using that 'confused' him as to the end of the runway. We just received a new video map that depicts the final approach courses for the LDA and RNAV approaches to Runway 35. This map is 'backwards' in it's depiction of the distance markings on final than all of the maps that we have. It makes the runway end appear one mile longer/further south than it really is. The Controller thought the B737 was on a mile final when he shipped the Lear; when in fact the B737 was on a two mile final instead. This gave the Lear more time to catch the B737.
TRACON Controller described a loss of separation event involving two successive arrival aircraft on visual approaches. The reporter listed a new 'video map' that may have been a contributing factor.