Narrative:

We departed mry for lax on the monterey 6 departure using runway 28L. The runway in use was 10R, but the wind was calm and we elected to use a runway 28L departure due to rapidly rising terrain off the departure end of runway 10R. The monterey 6 departure for runway 28L specifies 'climb on runway heading until leaving 1000 ft, or as directed by monterey tower, turn right to a 330 degree heading for vector.' we were cleared for takeoff just after another aircraft was cleared for the ILS 10R. After passing about 700 ft, the tower controller issued the instructions, 'after passing 300 ft turn left to 115 degrees, receiving prb proceed direct.' I interpreted this to mean that he was taking us off the SID and vectoring us, and that we were to maintain runway heading until 3000 ft, and then turn left to 115 degrees. My first officer, who was the PF, thought he heard, 'fly runway heading until 3000 ft, turn left to 115 degrees, receiving prb proceed direct.' we continued to fly runway heading, and after breaking out on top of the clouds, we could see the landing lights of the aircraft inbound on the ILS runway 10R. There appeared to be plenty of separation. At about 1500 ft, the controller queried us why we were not turning right to 330 degrees and instructed us to turn further right to 360 degrees. We complied with this request and I answered that we had interpreted his instructions as meaning to fly runway heading until 3000 ft, then turn left to 115 degrees and proceed direct prb when able. We then continued on to lax without incident. I feel that I was in error in my interpretation of the controller's instructions, but I do feel that his instructions were unclr and subject to misinterp. If he would have said, 'fly the monterey 6 departure, at 3000 ft turn left to 115 degrees, receiving prb proceed direct,' the meaning of his instructions would have been clear. The fact is that we fly other sids that are interrupted and broken off by receiving a radar vector. This is that caused me to misinterpret the controller's instructions.

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Original NASA ASRS Text

Title: ACR ON SID MISINTERPRETS CLB CLRNC AND DOESN'T TURN. TFC OPPOSITE DIRECTION ON APCH AND ATC HAS TO VECTOR FOR SEPARATION.

Narrative: WE DEPARTED MRY FOR LAX ON THE MONTEREY 6 DEP USING RWY 28L. THE RWY IN USE WAS 10R, BUT THE WIND WAS CALM AND WE ELECTED TO USE A RWY 28L DEP DUE TO RAPIDLY RISING TERRAIN OFF THE DEP END OF RWY 10R. THE MONTEREY 6 DEP FOR RWY 28L SPECIFIES 'CLB ON RWY HDG UNTIL LEAVING 1000 FT, OR AS DIRECTED BY MONTEREY TWR, TURN R TO A 330 DEG HDG FOR VECTOR.' WE WERE CLRED FOR TKOF JUST AFTER ANOTHER ACFT WAS CLRED FOR THE ILS 10R. AFTER PASSING ABOUT 700 FT, THE TWR CTLR ISSUED THE INSTRUCTIONS, 'AFTER PASSING 300 FT TURN L TO 115 DEGS, RECEIVING PRB PROCEED DIRECT.' I INTERPRETED THIS TO MEAN THAT HE WAS TAKING US OFF THE SID AND VECTORING US, AND THAT WE WERE TO MAINTAIN RWY HDG UNTIL 3000 FT, AND THEN TURN L TO 115 DEGS. MY FO, WHO WAS THE PF, THOUGHT HE HEARD, 'FLY RWY HDG UNTIL 3000 FT, TURN L TO 115 DEGS, RECEIVING PRB PROCEED DIRECT.' WE CONTINUED TO FLY RWY HDG, AND AFTER BREAKING OUT ON TOP OF THE CLOUDS, WE COULD SEE THE LNDG LIGHTS OF THE ACFT INBOUND ON THE ILS RWY 10R. THERE APPEARED TO BE PLENTY OF SEPARATION. AT ABOUT 1500 FT, THE CTLR QUERIED US WHY WE WERE NOT TURNING R TO 330 DEGS AND INSTRUCTED US TO TURN FURTHER R TO 360 DEGS. WE COMPLIED WITH THIS REQUEST AND I ANSWERED THAT WE HAD INTERPRETED HIS INSTRUCTIONS AS MEANING TO FLY RWY HDG UNTIL 3000 FT, THEN TURN L TO 115 DEGS AND PROCEED DIRECT PRB WHEN ABLE. WE THEN CONTINUED ON TO LAX WITHOUT INCIDENT. I FEEL THAT I WAS IN ERROR IN MY INTERPRETATION OF THE CTLR'S INSTRUCTIONS, BUT I DO FEEL THAT HIS INSTRUCTIONS WERE UNCLR AND SUBJECT TO MISINTERP. IF HE WOULD HAVE SAID, 'FLY THE MONTEREY 6 DEP, AT 3000 FT TURN L TO 115 DEGS, RECEIVING PRB PROCEED DIRECT,' THE MEANING OF HIS INSTRUCTIONS WOULD HAVE BEEN CLR. THE FACT IS THAT WE FLY OTHER SIDS THAT ARE INTERRUPTED AND BROKEN OFF BY RECEIVING A RADAR VECTOR. THIS IS THAT CAUSED ME TO MISINTERPRET THE CTLR'S INSTRUCTIONS.

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.