Narrative:

I was working local control. VFR weather. An E-170 was very short final when I observed a target on the asde-X just south of a taxiway intersection. I immediately notified the supervisor and picked up some binoculars along with multiple others in the tower cab. We all observed nothing in that area. The arrival was already passed the threshold and in his flare when the asde-X alerted 'warning; runway xx occupied' and lit up the false target and the arrival aircraft. I felt it would be unsafe to send the aircraft around since they were in a critical stage of flight and continued monitoring the situation; scanning the area along with the supervisor on duty. Once safely rolling out; I asked the aircraft to scan the area as they taxied by and they observed nothing. The false target disappeared shortly thereafter. A county mobile vehicle got on the runway about 5 minutes later to do a daily routine inspection. I asked the county mobile vehicle to inspect the area also and they didn't see anything either.I feel like I handled the situation correctly. I felt it would be very unsafe to send the arrival on short final around at the time the asde-X went off (especially after observing nothing in the area of the false target). Had I observed any disturbance in the area of the false target; I would have taken a different course of action.

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Original NASA ASRS Text

Title: Local Controller reported a false ASDE-X warning of conflicting traffic on the runway while an aircraft was on short final. The controllers in the Tower scanned the area; but were unable to find a reason for the erroneous warning and the aircraft landed uneventfully.

Narrative: I was working Local Control. VFR weather. An E-170 was very short final when I observed a target on the ASDE-X just south of a taxiway intersection. I immediately notified the supervisor and picked up some binoculars along with multiple others in the tower cab. We all observed nothing in that area. The arrival was already passed the threshold and in his flare when the ASDE-X alerted 'warning; RWY XX occupied' and lit up the false target and the arrival aircraft. I felt it would be unsafe to send the aircraft around since they were in a critical stage of flight and continued monitoring the situation; scanning the area along with the supervisor on duty. Once safely rolling out; I asked the aircraft to scan the area as they taxied by and they observed nothing. The false target disappeared shortly thereafter. A county mobile vehicle got on the runway about 5 minutes later to do a daily routine inspection. I asked the county mobile vehicle to inspect the area also and they didn't see anything either.I feel like I handled the situation correctly. I felt it would be very unsafe to send the arrival on short final around at the time the ASDE-X went off (especially after observing nothing in the area of the false target). Had I observed any disturbance in the area of the false target; I would have taken a different course of action.

Data retrieved from NASA's ASRS site 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.