Narrative:

Our flight was on the ILS to runway 20L and cleared for the approach to runway 20L when handed us off to tower on 128.15. Upon checking in, we were told to circle to runway 20C and contact tower on 118.6. We did so. The tower cleared us to land on runway 20C. On short final (1/2 - 1/4 mi), we received a TCASII alert for 'traffic, traffic,' not unusual in view of the fact that simultaneous visual approachs are often done on runway 20C and runway 20R. However, when we received an RA of 'climb, climb, now' from the TCASII and the traffic on the runway 20R approach was not in sight, an immediate go around order was issued by myself and we did so with the proper notification to tower. Subsequently, we shot another approach to runway 20R and landed without incident. Ground control instructed us to call the tower when we were parked, a job that I left to the PIC. I believe that the aircraft on 20R strayed left of course into our 'space,' as we were directly on extended centerline of runway 20C and, hence, the TCASII alert. The winds were very gusty from the right. I am not sure exactly the degrees and quantity, but it was around 15 KTS of direct crosswind. In conclusion, I feel myself and my captain violated no regulations and acted in a nothing but safe manner with complete thoughts of safety for ourselves, our aircraft, and most of all our passenger in avoiding a very possible, maybe probable, midair collision.

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Original NASA ASRS Text

Title: AN ACR LTT CREW MADE A GAR IN RESPONSE TO A TCASII COMMAND.

Narrative: OUR FLT WAS ON THE ILS TO RWY 20L AND CLRED FOR THE APCH TO RWY 20L WHEN HANDED US OFF TO TWR ON 128.15. UPON CHKING IN, WE WERE TOLD TO CIRCLE TO RWY 20C AND CONTACT TWR ON 118.6. WE DID SO. THE TWR CLRED US TO LAND ON RWY 20C. ON SHORT FINAL (1/2 - 1/4 MI), WE RECEIVED A TCASII ALERT FOR 'TFC, TFC,' NOT UNUSUAL IN VIEW OF THE FACT THAT SIMULTANEOUS VISUAL APCHS ARE OFTEN DONE ON RWY 20C AND RWY 20R. HOWEVER, WHEN WE RECEIVED AN RA OF 'CLB, CLB, NOW' FROM THE TCASII AND THE TFC ON THE RWY 20R APCH WAS NOT IN SIGHT, AN IMMEDIATE GAR ORDER WAS ISSUED BY MYSELF AND WE DID SO WITH THE PROPER NOTIFICATION TO TWR. SUBSEQUENTLY, WE SHOT ANOTHER APCH TO RWY 20R AND LANDED WITHOUT INCIDENT. GND CTL INSTRUCTED US TO CALL THE TWR WHEN WE WERE PARKED, A JOB THAT I LEFT TO THE PIC. I BELIEVE THAT THE ACFT ON 20R STRAYED L OF COURSE INTO OUR 'SPACE,' AS WE WERE DIRECTLY ON EXTENDED CTRLINE OF RWY 20C AND, HENCE, THE TCASII ALERT. THE WINDS WERE VERY GUSTY FROM THE R. I AM NOT SURE EXACTLY THE DEGREES AND QUANTITY, BUT IT WAS AROUND 15 KTS OF DIRECT XWIND. IN CONCLUSION, I FEEL MYSELF AND MY CAPT VIOLATED NO REGS AND ACTED IN A NOTHING BUT SAFE MANNER WITH COMPLETE THOUGHTS OF SAFETY FOR OURSELVES, OUR ACFT, AND MOST OF ALL OUR PAX IN AVOIDING A VERY POSSIBLE, MAYBE PROBABLE, MIDAIR COLLISION.

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.