Narrative:

I am a B737 check airman and had displaced the first officer for the flight. While descending into dfw and cleared to 11000 ft, we were given holding at cqy approximately 15 mi prior to the fix. This was due to a change of landing direction at dfw. The controller had asked us to expedite descent through FL200. At approximately FL210 in our expedited descent, I noticed on the TCASII an aircraft ahead and to the left (amber). We were beginning our turn in holding at the same time, and I saw him ahead and below us at FL190. At the same time, we had a TCASII a to stop our descent, which I did at FL203. We notified ATC of the RA, and asked about our clearance to 11000 ft. He said he thought he had given us an amended clearance for FL200. We did not hear that clearance. The controller was very busy because of the change of runways at dfw and gave us the holding clearance with very short notice. At no time was there a separation conflict as we stopped our descent and maintained FL200. Once again, TCASII has proven itself an invaluable tool in the cockpit. Supplemental information from acn 630121: separation in distance at first sighting: 2000 ft. Proximity at closest point horizontally and vertically: 500 ft/800 ft. Degree of evasive action: leveled and climbed to FL200. No injuries.

Google
 

Original NASA ASRS Text

Title: B737-800 EXPERIENCES TCASII RA DSNDING INTO DFW. CTLR CLAIMS AMENDED CLRNC GIVEN, BUT FLT CREW DO NOT HEAR OR ACKNOWLEDGE IT.

Narrative: I AM A B737 CHK AIRMAN AND HAD DISPLACED THE FO FOR THE FLT. WHILE DSNDING INTO DFW AND CLRED TO 11000 FT, WE WERE GIVEN HOLDING AT CQY APPROX 15 MI PRIOR TO THE FIX. THIS WAS DUE TO A CHANGE OF LNDG DIRECTION AT DFW. THE CTLR HAD ASKED US TO EXPEDITE DSCNT THROUGH FL200. AT APPROX FL210 IN OUR EXPEDITED DSCNT, I NOTICED ON THE TCASII AN ACFT AHEAD AND TO THE L (AMBER). WE WERE BEGINNING OUR TURN IN HOLDING AT THE SAME TIME, AND I SAW HIM AHEAD AND BELOW US AT FL190. AT THE SAME TIME, WE HAD A TCASII A TO STOP OUR DSCNT, WHICH I DID AT FL203. WE NOTIFIED ATC OF THE RA, AND ASKED ABOUT OUR CLRNC TO 11000 FT. HE SAID HE THOUGHT HE HAD GIVEN US AN AMENDED CLRNC FOR FL200. WE DID NOT HEAR THAT CLRNC. THE CTLR WAS VERY BUSY BECAUSE OF THE CHANGE OF RWYS AT DFW AND GAVE US THE HOLDING CLRNC WITH VERY SHORT NOTICE. AT NO TIME WAS THERE A SEPARATION CONFLICT AS WE STOPPED OUR DSCNT AND MAINTAINED FL200. ONCE AGAIN, TCASII HAS PROVEN ITSELF AN INVALUABLE TOOL IN THE COCKPIT. SUPPLEMENTAL INFO FROM ACN 630121: SEPARATION IN DISTANCE AT FIRST SIGHTING: 2000 FT. PROX AT CLOSEST POINT HORIZLY AND VERTLY: 500 FT/800 FT. DEGREE OF EVASIVE ACTION: LEVELED AND CLBED TO FL200. NO INJURIES.

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.