Narrative:

Climbing through FL260 we received a 'traffic, traffic' alert from our TCASII, quickly followed by 'reduce climb' and the visual indication of a target 'red square' right over us. I began immediate descent and copilot began radio xmissions to ZID. TCASII kept on warning 'descend, descend' and I descended to almost FL245 before we visually determined TCASII warning was wrong. It took the copilot 4 radio xmissions to center before they answered. They were working multiple frequencys, and couldn't hear us. They said there was no other traffic, IFR or VFR.

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Original NASA ASRS Text

Title: FLC OF MLG HAS FALSE TCASII ALERT, DSNDS ACCORDINGLY BUT ATC SAYS NO TFC IN AREA.

Narrative: CLBING THROUGH FL260 WE RECEIVED A 'TFC, TFC' ALERT FROM OUR TCASII, QUICKLY FOLLOWED BY 'REDUCE CLB' AND THE VISUAL INDICATION OF A TARGET 'RED SQUARE' RIGHT OVER US. I BEGAN IMMEDIATE DSCNT AND COPLT BEGAN RADIO XMISSIONS TO ZID. TCASII KEPT ON WARNING 'DSND, DSND' AND I DSNDED TO ALMOST FL245 BEFORE WE VISUALLY DETERMINED TCASII WARNING WAS WRONG. IT TOOK THE COPLT 4 RADIO XMISSIONS TO CTR BEFORE THEY ANSWERED. THEY WERE WORKING MULTIPLE FREQS, AND COULDN'T HEAR US. THEY SAID THERE WAS NO OTHER TFC, IFR OR VFR.

Data retrieved from NASA's ASRS site as of July 2007 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.