Narrative:

Entering dfw on blue ridge 6 arrival/past hamak international downwind heading 180 assigned. Cleared to descend from 11000-6000 ft. Out of 7000 ft for 6000 ft controller transmitted traffic advisories for 3 different aircraft crossing our track (1 off the nose/1 climbing right to left under us/1 on right side of aircraft) TCASII indicated 1 under us going right to left and climbing. I (PF) looked to the left side to find the aircraft as it became visible. It appeared crossing right to left aft of my seat position and I estimate about 2000- 2500 ft below us passing well clear. As I looked back into the cockpit I noticed 5700 ft on my altimeter and immediately added power -- returning the aircraft to 6000 ft immediately upon discovering the deviation. No conflict was apparent -- the controller made no comment concerning said deviation and in fact as soon as I returned to 6000 ft cleared me to 3000 ft with a right turn to a 260 degree heading. A normal approach and landing followed. Lesson learned let TCASII tell you the aircraft is too close before you distract yourself to look and find the aircraft.

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Original NASA ASRS Text

Title: CAPT OF AN LGT DSNDED BELOW ASSIGNED DSCNT ALT DUE TO TCASII AND TA WATCH DISTR.

Narrative: ENTERING DFW ON BLUE RIDGE 6 ARR/PAST HAMAK INTL DOWNWIND HDG 180 ASSIGNED. CLRED TO DSND FROM 11000-6000 FT. OUT OF 7000 FT FOR 6000 FT CTLR XMITTED TFC ADVISORIES FOR 3 DIFFERENT ACFT XING OUR TRACK (1 OFF THE NOSE/1 CLBING R TO L UNDER US/1 ON R SIDE OF ACFT) TCASII INDICATED 1 UNDER US GOING R TO L AND CLBING. I (PF) LOOKED TO THE L SIDE TO FIND THE ACFT AS IT BECAME VISIBLE. IT APPEARED XING R TO L AFT OF MY SEAT POS AND I ESTIMATE ABOUT 2000- 2500 FT BELOW US PASSING WELL CLR. AS I LOOKED BACK INTO THE COCKPIT I NOTICED 5700 FT ON MY ALTIMETER AND IMMEDIATELY ADDED PWR -- RETURNING THE ACFT TO 6000 FT IMMEDIATELY UPON DISCOVERING THE DEV. NO CONFLICT WAS APPARENT -- THE CTLR MADE NO COMMENT CONCERNING SAID DEV AND IN FACT AS SOON AS I RETURNED TO 6000 FT CLRED ME TO 3000 FT WITH A R TURN TO A 260 DEG HDG. A NORMAL APCH AND LNDG FOLLOWED. LESSON LEARNED LET TCASII TELL YOU THE ACFT IS TOO CLOSE BEFORE YOU DISTRACT YOURSELF TO LOOK AND FIND THE ACFT.

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.