Narrative:

Our flight was on position and hold on runway 25L at lax. A saab 340 aircraft was cleared for takeoff on runway 25R. As the saab began its takeoff roll, our flight was cleared for takeoff. As we lifted off, lax tower told our flight to keep the saab on our right side and maintain visual separation. (We never said we had the saab in sight.) our flight was going to san diego and the saab aircraft was destined for palm springs. Both aircraft were on the same SID and began left turns to 200 degrees at, basically, crossing the shoreline. The saab was then switched to departure and was given a further left turn to 110 degrees. With this new heading, the saab turned directly in front of my aircraft, and there was no way to keep it off my right side. The saab was slightly above my aircraft and climbing, so I elected to level and then descend 300 ft. I went under the saab by 800 ft and received a TA. Even if I had called the saab in sight and stated that I could maintain visual separation, there is no way I could have anticipated that departure control would turn the aircraft directly in front of me. Upon landing in san diego, I called socal TRACON and lax tower. The lax tower chief indicated that the lax controller made a mistake and should have departed my flight from runway 25R and the saab from runway 25L. Lax tower further indicated that socal departure's radar cannot determine which aircraft departed which runway. Socal departure assumed that the saab departed runway 25L and my flight departed runway 25R. With this situation, the saab's left turn to 110 degrees would have taken the aircraft further away from my aircraft, rather than straight into our aircraft (ie, a conflict would not have occurred).

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Original NASA ASRS Text

Title: AN EMB120 PIC'S RPT ON A POTENTIAL CONFLICT WITH AN SF340 ON A PARALLEL DEP PROC FROM LAX. IT COULD HAVE BEEN AN NMAC BUT FOR THE CAPT'S LEVELING OFF TO AVOID THE SAAB 340. THE 2 ACFT HAD A SIMULTANEOUS DEP FROM RWYS 25L&R WITH THE SAAB 340 MAKING A VECTORED L TURN IN FRONT OF THE EMB120.

Narrative: OUR FLT WAS ON POS AND HOLD ON RWY 25L AT LAX. A SAAB 340 ACFT WAS CLRED FOR TKOF ON RWY 25R. AS THE SAAB BEGAN ITS TKOF ROLL, OUR FLT WAS CLRED FOR TKOF. AS WE LIFTED OFF, LAX TWR TOLD OUR FLT TO KEEP THE SAAB ON OUR R SIDE AND MAINTAIN VISUAL SEPARATION. (WE NEVER SAID WE HAD THE SAAB IN SIGHT.) OUR FLT WAS GOING TO SAN DIEGO AND THE SAAB ACFT WAS DESTINED FOR PALM SPRINGS. BOTH ACFT WERE ON THE SAME SID AND BEGAN L TURNS TO 200 DEGS AT, BASICALLY, XING THE SHORELINE. THE SAAB WAS THEN SWITCHED TO DEP AND WAS GIVEN A FURTHER L TURN TO 110 DEGS. WITH THIS NEW HDG, THE SAAB TURNED DIRECTLY IN FRONT OF MY ACFT, AND THERE WAS NO WAY TO KEEP IT OFF MY R SIDE. THE SAAB WAS SLIGHTLY ABOVE MY ACFT AND CLBING, SO I ELECTED TO LEVEL AND THEN DSND 300 FT. I WENT UNDER THE SAAB BY 800 FT AND RECEIVED A TA. EVEN IF I HAD CALLED THE SAAB IN SIGHT AND STATED THAT I COULD MAINTAIN VISUAL SEPARATION, THERE IS NO WAY I COULD HAVE ANTICIPATED THAT DEP CTL WOULD TURN THE ACFT DIRECTLY IN FRONT OF ME. UPON LNDG IN SAN DIEGO, I CALLED SOCAL TRACON AND LAX TWR. THE LAX TWR CHIEF INDICATED THAT THE LAX CTLR MADE A MISTAKE AND SHOULD HAVE DEPARTED MY FLT FROM RWY 25R AND THE SAAB FROM RWY 25L. LAX TWR FURTHER INDICATED THAT SOCAL DEP'S RADAR CANNOT DETERMINE WHICH ACFT DEPARTED WHICH RWY. SOCAL DEP ASSUMED THAT THE SAAB DEPARTED RWY 25L AND MY FLT DEPARTED RWY 25R. WITH THIS SIT, THE SAAB'S L TURN TO 110 DEGS WOULD HAVE TAKEN THE ACFT FURTHER AWAY FROM MY ACFT, RATHER THAN STRAIGHT INTO OUR ACFT (IE, A CONFLICT WOULD NOT HAVE OCCURRED).

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.