Narrative:

Aircraft system 'TCASII' issued a 'TA' followed by a 'RA.' traffic was displayed as a yellow DOT on my airborne radar screen followed by a 'red square' and an RA to 'descend, descend' -- 12 seconds (approximately). TCASII issued 'clear of conflict, clear of conflict.' radar vectors to about 2700, then we climbed back to 3000. Aircraft continued to a normal approach and landing without further incident. (ATC was informed). Callback conversation with reporter revealed the following information: the widebody transport captain reporter of this incident is a strong fan of the TCASII system. He is sure that this was a real warning, not false, and that TCASII saved the day.

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Original NASA ASRS Text

Title: A WDB ACR CREW HAD A TCASII COMMAND TO 'CLB' IN IMC CONDITIONS. THE RPTR KNOWS THAT THIS WAS A REAL THREAT.

Narrative: ACFT SYS 'TCASII' ISSUED A 'TA' FOLLOWED BY A 'RA.' TFC WAS DISPLAYED AS A YELLOW DOT ON MY AIRBORNE RADAR SCREEN FOLLOWED BY A 'RED SQUARE' AND AN RA TO 'DSND, DSND' -- 12 SECONDS (APPROX). TCASII ISSUED 'CLR OF CONFLICT, CLR OF CONFLICT.' RADAR VECTORS TO ABOUT 2700, THEN WE CLBED BACK TO 3000. ACFT CONTINUED TO A NORMAL APCH AND LNDG WITHOUT FURTHER INCIDENT. (ATC WAS INFORMED). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE WDB CAPT RPTR OF THIS INCIDENT IS A STRONG FAN OF THE TCASII SYS. HE IS SURE THAT THIS WAS A REAL WARNING, NOT FALSE, AND THAT TCASII SAVED THE DAY.

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.