Narrative:

The TCASII suddenly announced 'climb, climb' while the vsi's lit up red indicating a roc greater than 2000 FPM should be initiated. This was not preceded by a TA, but since we had the radar on the screen, (TCASII and radar share the same screen) we did not have a visual picture of what the RA was about. I disconnected the autoplt and began a climb. I simultaneously told the first officer to notify ATC and pressed the button to display the TCASII information on the screen. It showed traffic at our altitude (16000) at our 9:30 position and less than 2 mi. At this time we broke out of the cloud we were in and did not see any traffic in that area, and the image disappeared from TCASII. Center advised us that he had no other traffic in the area except at 6000 ft and that our altitude deviation was not a problem and to maintain 16000 ft. The image reappeared on the TCASII again as a yellow TA for just a moment. The highest altitude noted on the altimeter was 16350 ft while center said he had us at 16500 ft.

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Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION AS FLC RESPONDS TO TCASII RA. FALSE WARNING.

Narrative: THE TCASII SUDDENLY ANNOUNCED 'CLB, CLB' WHILE THE VSI'S LIT UP RED INDICATING A ROC GREATER THAN 2000 FPM SHOULD BE INITIATED. THIS WAS NOT PRECEDED BY A TA, BUT SINCE WE HAD THE RADAR ON THE SCREEN, (TCASII AND RADAR SHARE THE SAME SCREEN) WE DID NOT HAVE A VISUAL PICTURE OF WHAT THE RA WAS ABOUT. I DISCONNECTED THE AUTOPLT AND BEGAN A CLB. I SIMULTANEOUSLY TOLD THE FO TO NOTIFY ATC AND PRESSED THE BUTTON TO DISPLAY THE TCASII INFO ON THE SCREEN. IT SHOWED TFC AT OUR ALT (16000) AT OUR 9:30 POS AND LESS THAN 2 MI. AT THIS TIME WE BROKE OUT OF THE CLOUD WE WERE IN AND DID NOT SEE ANY TFC IN THAT AREA, AND THE IMAGE DISAPPEARED FROM TCASII. CTR ADVISED US THAT HE HAD NO OTHER TFC IN THE AREA EXCEPT AT 6000 FT AND THAT OUR ALTDEV WAS NOT A PROBLEM AND TO MAINTAIN 16000 FT. THE IMAGE REAPPEARED ON THE TCASII AGAIN AS A YELLOW TA FOR JUST A MOMENT. THE HIGHEST ALT NOTED ON THE ALTIMETER WAS 16350 FT WHILE CTR SAID HE HAD US AT 16500 FT.

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.