Narrative:

Was cleared for visual with ILS 23 to clt and cleared to land. In early flare approaching the hump in the runway at about 30 feet clt tower instructed us to go-around. I was surprised and advanced thrust levers to toga saying go-around toga; following the go-around procedures in our operating manual and instructed to fly runway heading to 4;000 ft rather than the published missed approach.I had the first officer request the reason for a go-around at such a low altitude. Clt tower said they issued a ground radar alert which was a mandatory go-around. We never observed any obstructions on the runway but complied with the tower's instructions. After clean-up I told my first officer to tell the people in the back something on the PA that I had the radio and aircraft until he got back with me. We were vectored back for and a visual approach and landing on runway 18R which was briefed prior to landing. I believe this go-around is associated with the adw (arrival departure window) system in charlotte although a recently retired controller I spoke with mentioned it is possible that something like tall grass blowing around could trigger a false runway warning. We never saw any type of conflict but executed a go-around from a low altitude over the runway without touching down.

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Original NASA ASRS Text

Title: A319 Captain reported being issued a go-around by CLT Tower below 50 feet. When queried as to the reason for the go-around the Tower stated 'ground radar alert.'

Narrative: Was cleared for visual with ILS 23 to CLT and cleared to land. In early flare approaching the hump in the runway at about 30 feet CLT tower instructed us to go-around. I was surprised and advanced thrust levers to TOGA saying go-around TOGA; following the go-around procedures in our operating manual and instructed to fly runway heading to 4;000 ft rather than the published missed approach.I had the FO request the reason for a go-around at such a low altitude. CLT tower said they issued a ground radar alert which was a mandatory go-around. We never observed any obstructions on the runway but complied with the tower's instructions. After clean-up I told my FO to tell the people in the back something on the PA that I had the radio and aircraft until he got back with me. We were vectored back for and a visual approach and landing on Runway 18R which was briefed prior to landing. I believe this go-around is associated with the ADW (Arrival Departure Window) system in Charlotte although a recently retired Controller I spoke with mentioned it is possible that something like tall grass blowing around could trigger a false runway warning. We never saw any type of conflict but executed a go-around from a low altitude over the runway without touching down.

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.