Narrative:

Taking off runway 15L with a left turn to heading 010 in houston; [an A320] departed runway 15R approximately 15 seconds before us. We did note him rotate and we heard him assigned to fly runway heading after takeoff. We rotated and almost right after; we saw the A320 begin a left turn across our departure path. Since I was the flying pilot; I immediately slowed the climb of the aircraft and the first officer (first officer) told iah ATC that the [A320] aircraft was turning across our departure path and that we were heading straight out. The tower controller immediately instructed the A320 to turn right and had us stop at 2000 ft. We were still unsure of where to actually point the aircraft as the [A320] was now turning right back across our departure path again. The tower controller had us turn left to 020 and then contact departure. We came within 800-900 feet of the A320. No TA or RA was received. We performed no maneuvers outside of the flight envelope. We did not declare an emergency but did deviate from our assigned clearance for the traffic conflict. The iah ATC facility controller handled this potential near midair collision in an exemplary fashion and did everything to ensure safety and separation for both aircraft.

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Original NASA ASRS Text

Title: B737NG Captain reported an airborne conflict occurred departing IAH when an A320 failed to follow his ATC clearance.

Narrative: Taking off runway 15L with a left turn to heading 010 in Houston; [an A320] departed runway 15R approximately 15 seconds before us. We did note him rotate and we heard him assigned to fly runway heading after takeoff. We rotated and almost right after; we saw the A320 begin a left turn across our departure path. Since I was the flying pilot; I immediately slowed the climb of the aircraft and the First Officer (FO) told IAH ATC that the [A320] aircraft was turning across our departure path and that we were heading straight out. The Tower Controller immediately instructed the A320 to turn right and had us stop at 2000 FT. We were still unsure of where to actually point the aircraft as the [A320] was now turning right back across our departure path again. The Tower Controller had us turn left to 020 and then contact Departure. We came within 800-900 feet of the A320. No TA or RA was received. We performed no maneuvers outside of the flight envelope. We did not declare an emergency but did deviate from our assigned clearance for the traffic conflict. The IAH ATC facility controller handled this potential NMAC in an exemplary fashion and did everything to ensure safety and separation for both aircraft.

Data retrieved from NASA's ASRS site 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.