Narrative:

I was working 1 of 2 local control position in the tower at the time of the incident. Small aircraft X departed runway 15L VFR. The other local controller issued him a left turn to a heading of 120 degree which he acknowledged. Moments later I cleared air carrier X for takeoff on runway 15R. The other local controller then began procedures to combine his position onto mine. The pilot of small aircraft Y for some unknown reason, made a right turn instead of left. (The tape revealed that the pilot read back to the local controller a heading of 120 degree, and also told the departure controller he was turning to 120 degree.) air carrier X had to take evasive action immediately after takeoff to avoid small aircraft Y. I'm told that this incident is probably going to be processed as a pilot deviation. Supplemental information from acn 178433: departed runway 15L and was given a left turn to heading 120 and told to contact departure. The pilot acknowledged the transmission and read back the heading correctly. The pilot checked in with departure and stated again the tower assigned heading of 120. Instead of turning left, small aircraft X entered a right turn which placed him in front of a departing air carrier Y that was taking off of runway 15R. Air carrier Y informed tower that he had traffic at 2 O'clock and 1.5 (altitude) and that he was turning to avoid conflict. A call was placed to departure to see what small aircraft X was doing. Small aircraft X again acknowledged heading and said 'I guess we better get back over there.' it was later learned that the air carrier received a TCAS traffic alert, observed the traffic visually and turned to avoid conflict. I feel this incident occurred by a lack of awareness by the small aircraft X pilot as to his actual heading versus ATC assigned heading.

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Original NASA ASRS Text

Title: SMA X NON ADHERENCE TO ATC CLRNC HAD NMAC WITH ACR Y. PLT DEV.

Narrative: I WAS WORKING 1 OF 2 LCL CTL POS IN THE TWR AT THE TIME OF THE INCIDENT. SMA X DEPARTED RWY 15L VFR. THE OTHER LCL CTLR ISSUED HIM A L TURN TO A HDG OF 120 DEG WHICH HE ACKNOWLEDGED. MOMENTS LATER I CLRED ACR X FOR TKOF ON RWY 15R. THE OTHER LCL CTLR THEN BEGAN PROCS TO COMBINE HIS POS ONTO MINE. THE PLT OF SMA Y FOR SOME UNKNOWN REASON, MADE A R TURN INSTEAD OF L. (THE TAPE REVEALED THAT THE PLT READ BACK TO THE LCL CTLR A HDG OF 120 DEG, AND ALSO TOLD THE DEP CTLR HE WAS TURNING TO 120 DEG.) ACR X HAD TO TAKE EVASIVE ACTION IMMEDIATELY AFTER TKOF TO AVOID SMA Y. I'M TOLD THAT THIS INCIDENT IS PROBABLY GOING TO BE PROCESSED AS A PLT DEV. SUPPLEMENTAL INFO FROM ACN 178433: DEPARTED RWY 15L AND WAS GIVEN A L TURN TO HDG 120 AND TOLD TO CONTACT DEP. THE PLT ACKNOWLEDGED THE XMISSION AND READ BACK THE HDG CORRECTLY. THE PLT CHKED IN WITH DEP AND STATED AGAIN THE TWR ASSIGNED HDG OF 120. INSTEAD OF TURNING L, SMA X ENTERED A R TURN WHICH PLACED HIM IN FRONT OF A DEPARTING ACR Y THAT WAS TAKING OFF OF RWY 15R. ACR Y INFORMED TWR THAT HE HAD TFC AT 2 O'CLOCK AND 1.5 (ALT) AND THAT HE WAS TURNING TO AVOID CONFLICT. A CALL WAS PLACED TO DEP TO SEE WHAT SMA X WAS DOING. SMA X AGAIN ACKNOWLEDGED HDG AND SAID 'I GUESS WE BETTER GET BACK OVER THERE.' IT WAS LATER LEARNED THAT THE ACR RECEIVED A TCAS TFC ALERT, OBSERVED THE TFC VISUALLY AND TURNED TO AVOID CONFLICT. I FEEL THIS INCIDENT OCCURRED BY A LACK OF AWARENESS BY THE SMA X PLT AS TO HIS ACTUAL HDG VERSUS ATC ASSIGNED HDG.

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.