Narrative:

Cleared for takeoff, fly 235 degrees, maintain 5000 ft. Passing about 1000 ft the TCASII began to sound 'traffic, traffic' as it occasionally does at that point. I took a frequency change to departure at this time and reported. The first words I heard were 'do you still have commuter in sight'? I replied, 'negative, but I have the large aircraft at 12 O'clock'. 10 seconds later I got a second TCASII warning and instructions to turn to 160 degrees and climb to 13000 ft. This seemed early but because of the second (unusual) TCASII warning, the commuter report and possible coast traffic, reasonable. I repeated the heading and altitude and began to turn, continuing my climb. During the turn, passing about 4000 ft departure advised me to stop turn and maintain 5000 ft, which I did. I reported an large transport in sight to my right and well above me. He had taken off in front of me and made his climbing left turn towards lax. It was tense at this time. Visibility was good, but I was still concerned about the commuter call and possible coast traffic. Departure later advised me that I had taken another aircraft's turn, company ccb. I made a TCASII system logbook writeup since I was unable to determine the validity of the warning. There were no RA's, only TA's. The system checked ok. The similarity of call signs has been brought to the attention of the company. A TCASII event questionnaire has been completed suggesting that TCASII volume be inhibited for the first 90 seconds after takeoff.

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Original NASA ASRS Text

Title: ACR LGT TRACK HDG DEV ON VECTOR DEP FROM LAX.

Narrative: CLRED FOR TKOF, FLY 235 DEGS, MAINTAIN 5000 FT. PASSING ABOUT 1000 FT THE TCASII BEGAN TO SOUND 'TFC, TFC' AS IT OCCASIONALLY DOES AT THAT POINT. I TOOK A FREQ CHANGE TO DEP AT THIS TIME AND RPTED. THE FIRST WORDS I HEARD WERE 'DO YOU STILL HAVE COMMUTER IN SIGHT'? I REPLIED, 'NEGATIVE, BUT I HAVE THE LARGE ACFT AT 12 O'CLOCK'. 10 SECONDS LATER I GOT A SECOND TCASII WARNING AND INSTRUCTIONS TO TURN TO 160 DEGS AND CLB TO 13000 FT. THIS SEEMED EARLY BUT BECAUSE OF THE SECOND (UNUSUAL) TCASII WARNING, THE COMMUTER RPT AND POSSIBLE COAST TFC, REASONABLE. I REPEATED THE HDG AND ALT AND BEGAN TO TURN, CONTINUING MY CLB. DURING THE TURN, PASSING ABOUT 4000 FT DEP ADVISED ME TO STOP TURN AND MAINTAIN 5000 FT, WHICH I DID. I RPTED AN LGT IN SIGHT TO MY R AND WELL ABOVE ME. HE HAD TAKEN OFF IN FRONT OF ME AND MADE HIS CLBING L TURN TOWARDS LAX. IT WAS TENSE AT THIS TIME. VISIBILITY WAS GOOD, BUT I WAS STILL CONCERNED ABOUT THE COMMUTER CALL AND POSSIBLE COAST TFC. DEP LATER ADVISED ME THAT I HAD TAKEN ANOTHER ACFT'S TURN, COMPANY CCB. I MADE A TCASII SYS LOGBOOK WRITEUP SINCE I WAS UNABLE TO DETERMINE THE VALIDITY OF THE WARNING. THERE WERE NO RA'S, ONLY TA'S. THE SYS CHKED OK. THE SIMILARITY OF CALL SIGNS HAS BEEN BROUGHT TO THE ATTN OF THE COMPANY. A TCASII EVENT QUESTIONNAIRE HAS BEEN COMPLETED SUGGESTING THAT TCASII VOLUME BE INHIBITED FOR THE FIRST 90 SECONDS AFTER TKOF.

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.