Narrative:

In the flare at 10-20 ft; ord tower told us to go around. The controller then told someone behind us to be prepared to go around also. There was no traffic anywhere near us; and there was ample separation with the aircraft behind us. After our go around and landing; I asked the tower controller why he made us go around. He told us that the ground radar sometimes mistakes rain showers in the area for aircraft and issues them an alert to make aircraft go around. Their procedure is to make aircraft go around even though they know it is not a potential conflict.

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Original NASA ASRS Text

Title: ACR FLT CREW EXPERIENCED AN ATC DIRECTED GAR DUE TO AN AMASS ALARM; REPORTEDLY; ACTIVATED BY RAINY CONDITIONS.

Narrative: IN THE FLARE AT 10-20 FT; ORD TWR TOLD US TO GO AROUND. THE CTLR THEN TOLD SOMEONE BEHIND US TO BE PREPARED TO GO AROUND ALSO. THERE WAS NO TFC ANYWHERE NEAR US; AND THERE WAS AMPLE SEPARATION WITH THE ACFT BEHIND US. AFTER OUR GAR AND LNDG; I ASKED THE TWR CTLR WHY HE MADE US GO AROUND. HE TOLD US THAT THE GND RADAR SOMETIMES MISTAKES RAIN SHOWERS IN THE AREA FOR ACFT AND ISSUES THEM AN ALERT TO MAKE ACFT GO AROUND. THEIR PROC IS TO MAKE ACFT GAR EVEN THOUGH THEY KNOW IT IS NOT A POTENTIAL CONFLICT.

Data retrieved from NASA's ASRS site as of January 2009 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.