Narrative:

We were cleared for takeoff to fly 'runway heading' climb to 10000 ft, on 3C at dfw. A small commuter aircraft had been cleared for takeoff on 3R just ahead of us. Flap retraction was started at 1000 ft AGL in IMC conditions. Suddenly our TCASII alarmed with a resolution to climb, and then monitor vertical speed, with the uui full red except for above the 2000 ft min climb. Target showed underneath my aircraft at 100 ft. There was no warning from departure control and when asked about it, they said they 'didn't think we were that close.' the commuter aircraft was not TCASII equipped. I feel the cause was the interpretation of the term 'runway heading.' we flew the extended centerline which was a magnetic heading of 035 degree. If the commuter flew a (runway heading of 030 degree), winds were from 050 degree, he would have wound up exactly where he did. We got limited warning because TCASII is limited in the wing tip positions. One solution would be for tower to eliminate the use of 'runway heading' and assign specific headings to parallel departures.

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Original NASA ASRS Text

Title: CAPT OF AN LGT ACR ACFT TOOK EVASIVE ACTION IN RESPONDING TO A TCASII WARNING RA BY INCREASING THE RATE OF CLB DURING INITIAL CLB AFTER TKOF. NMAC.

Narrative: WE WERE CLRED FOR TKOF TO FLY 'RWY HDG' CLB TO 10000 FT, ON 3C AT DFW. A SMALL COMMUTER ACFT HAD BEEN CLRED FOR TKOF ON 3R JUST AHEAD OF US. FLAP RETRACTION WAS STARTED AT 1000 FT AGL IN IMC CONDITIONS. SUDDENLY OUR TCASII ALARMED WITH A RESOLUTION TO CLB, AND THEN MONITOR VERT SPD, WITH THE UUI FULL RED EXCEPT FOR ABOVE THE 2000 FT MIN CLB. TARGET SHOWED UNDERNEATH MY ACFT AT 100 FT. THERE WAS NO WARNING FROM DEP CTL AND WHEN ASKED ABOUT IT, THEY SAID THEY 'DIDN'T THINK WE WERE THAT CLOSE.' THE COMMUTER ACFT WAS NOT TCASII EQUIPPED. I FEEL THE CAUSE WAS THE INTERPRETATION OF THE TERM 'RWY HDG.' WE FLEW THE EXTENDED CTRLINE WHICH WAS A MAG HDG OF 035 DEG. IF THE COMMUTER FLEW A (RWY HDG OF 030 DEG), WINDS WERE FROM 050 DEG, HE WOULD HAVE WOUND UP EXACTLY WHERE HE DID. WE GOT LIMITED WARNING BECAUSE TCASII IS LIMITED IN THE WING TIP POSITIONS. ONE SOLUTION WOULD BE FOR TWR TO ELIMINATE THE USE OF 'RWY HDG' AND ASSIGN SPECIFIC HDGS TO PARALLEL DEPS.

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.