Narrative:

Near midair collision. Departing dfw on runway 18L, we were a lightly loaded 170000 pounds, B757 captain flying, climbing rapidly after a standard power takeoff and climb 1 selected. We were flying at just over clean minimum maneuver and accelerating slowly due to being fairly close to the traffic which had departed in front of us. At about 3000-3500 ft, TCASII announced 'traffic, traffic.' I looked down at the screen, we had a yellow symbol, or maybe it turned red right then, I'm not certain, 900 ft above. I lowered the nose slightly due to the proximity of the other aircraft and immediately got a 'monitor vertical speed.' the green arc was at the top of the climb scale at about 3500-4000 FPM and had just 3 green lights lit. All the rest of the vsi was red. And, of course, the conflict aircraft symbol was red. The TCASII then announced 'climb crossing climb.' I pitched up to climb at the rate indicated by the green lights, selected 5 mi scale on the TCASII and saw the symbol at 200 ft above us and actually overlapping the wingtip of our aircraft symbol on the TCASII screen. I looked outside, found the other aircraft, lowered the nose and provided visual clearance. The other aircraft then turned away toward the east. There is no doubt that had I continued to follow the RA I would have flown through the other aircraft's vertical flight path. If we had then missed that aircraft, it would have been only laterally and by an uncomfortably small margin. It is possible that we would have collided. The TCASII did a good job of alerting us to the presence of the other aircraft, but, from our perspective, a nearly lethal job of resolving the conflict. I was surprised to see the climb command on the RA. Clearly, a leveloff or a reduced rate of climb for us would have resolved the conflict easily with much greater distance between the 2 aircraft. I called the tower and asked what had happened. The tower controller said he didn't know but that it must have been an aircraft from the east complex that had drifted over the west side. He told us to turn right to 190 degrees and contact departure control.

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Original NASA ASRS Text

Title: B757-200 CREW AND INTRUDING ACFT HAD AN NMAC JUST AFTER TKOF IN DFW CLASS B.

Narrative: NEAR MIDAIR COLLISION. DEPARTING DFW ON RWY 18L, WE WERE A LIGHTLY LOADED 170000 LBS, B757 CAPT FLYING, CLBING RAPIDLY AFTER A STANDARD PWR TKOF AND CLB 1 SELECTED. WE WERE FLYING AT JUST OVER CLEAN MINIMUM MANEUVER AND ACCELERATING SLOWLY DUE TO BEING FAIRLY CLOSE TO THE TFC WHICH HAD DEPARTED IN FRONT OF US. AT ABOUT 3000-3500 FT, TCASII ANNOUNCED 'TFC, TFC.' I LOOKED DOWN AT THE SCREEN, WE HAD A YELLOW SYMBOL, OR MAYBE IT TURNED RED RIGHT THEN, I'M NOT CERTAIN, 900 FT ABOVE. I LOWERED THE NOSE SLIGHTLY DUE TO THE PROX OF THE OTHER ACFT AND IMMEDIATELY GOT A 'MONITOR VERT SPD.' THE GREEN ARC WAS AT THE TOP OF THE CLB SCALE AT ABOUT 3500-4000 FPM AND HAD JUST 3 GREEN LIGHTS LIT. ALL THE REST OF THE VSI WAS RED. AND, OF COURSE, THE CONFLICT ACFT SYMBOL WAS RED. THE TCASII THEN ANNOUNCED 'CLB XING CLB.' I PITCHED UP TO CLB AT THE RATE INDICATED BY THE GREEN LIGHTS, SELECTED 5 MI SCALE ON THE TCASII AND SAW THE SYMBOL AT 200 FT ABOVE US AND ACTUALLY OVERLAPPING THE WINGTIP OF OUR ACFT SYMBOL ON THE TCASII SCREEN. I LOOKED OUTSIDE, FOUND THE OTHER ACFT, LOWERED THE NOSE AND PROVIDED VISUAL CLRNC. THE OTHER ACFT THEN TURNED AWAY TOWARD THE E. THERE IS NO DOUBT THAT HAD I CONTINUED TO FOLLOW THE RA I WOULD HAVE FLOWN THROUGH THE OTHER ACFT'S VERT FLT PATH. IF WE HAD THEN MISSED THAT ACFT, IT WOULD HAVE BEEN ONLY LATERALLY AND BY AN UNCOMFORTABLY SMALL MARGIN. IT IS POSSIBLE THAT WE WOULD HAVE COLLIDED. THE TCASII DID A GOOD JOB OF ALERTING US TO THE PRESENCE OF THE OTHER ACFT, BUT, FROM OUR PERSPECTIVE, A NEARLY LETHAL JOB OF RESOLVING THE CONFLICT. I WAS SURPRISED TO SEE THE CLB COMMAND ON THE RA. CLRLY, A LEVELOFF OR A REDUCED RATE OF CLB FOR US WOULD HAVE RESOLVED THE CONFLICT EASILY WITH MUCH GREATER DISTANCE BTWN THE 2 ACFT. I CALLED THE TWR AND ASKED WHAT HAD HAPPENED. THE TWR CTLR SAID HE DIDN'T KNOW BUT THAT IT MUST HAVE BEEN AN ACFT FROM THE E COMPLEX THAT HAD DRIFTED OVER THE W SIDE. HE TOLD US TO TURN R TO 190 DEGS AND CONTACT DEP CTL.

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.