Narrative:

A B757-200 was departing san on the POGGI2 departure climbing to FL230. A cessna caravan was climbing VFR to 13;500 for otay jump zone just north of the B757-200's route. The C-130 was VFR level at 13;000; heading westbound to the trident jump zone south of the B757-200's flight path. If you don't climb above the jump plane going into otay; you have to vector the aircraft around the jump zone because the SID routing is near the southern edge of the jump zone. The trident jump zone is approximately 2 miles south of the SID routing and the jump planes are generally never a factor. I was worried about the B757-200's rate of climb; because the caravan was climbing at the same rate. I stopped the caravan's climb at 11;700 and verified that the B757-200 was climbing through 12;500 to ensure separation. I switched the B757-200 to center and instead of responding with the frequency; the pilot stated that they were descending because of an RA. As he said this; I realized that the C-130 had turned northbound from the trident jump zone (level at 13;000 VFR). I told the C-130 to turn right heading 090 immediately. Once the B757-200 was clear of the C-130; the B757-200 was level at 12;000. The caravan was at the B757-200's 11 o'clock flying northbound and I told the caravan to continue northbound for traffic. I knew the B757-200 would pass south of the caravan and had him climb back to 14;000; then FL230. I think I had only worked 30 minutes total and it wasn't busy. I'm so disappointed in myself for not restricting the C-130 to a heading and that I didn't notice the C-130's route of flight before switching the B757-200. It makes you feel bad when an airplane is responding to an RA that you could have prevented. How could I have let that happen and be so confident about the C-130's route of flight? One heading and nothing would have happened. I have worked C-130s in that jump zone before and every time they have flown through the jump zone; gone westbound a few miles then turned back to the east. I should never have assumed that this C-130 would do the same thing. I'm always really vigilant about the north jump zone; because the aircraft working that area always climb high and generally always conflict with the airliners on the departure. I never issued traffic to the C-130 about the B757-200; or the B757-200 about the C-130. I just told the B757-200 about the caravan because the caravan was directly in his path. I should never have assumed that the C-130 was going to stay on course but I had given him no instructions. Recommendation; the only thing I can recommend for myself is to never assume what's going to happen. It doesn't make sense to me that I would assume he would fly through the jump zone; even though they typically always do that; but his altitude should have been a big red flag for me. I should have ensured that the B757-200 was above both aircraft before trying to give him a frequency change and I should have ensured the C-130's heading and given each other traffic advisories. I'm generally always giving VFR aircraft headings or instructions to keep them away from other aircraft so the fact that I didn't this time still baffles me. All I can do is thank the pilots for their immediate responses.

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Original NASA ASRS Text

Title: SCT Controller described a TCAS RA event between an air carrier departure and a Military 'jump' aircraft operating to a jump zone; the reporter acknowledging his/her assumptions led to the occurrence.

Narrative: A B757-200 was departing SAN on the POGGI2 departure climbing to FL230. A Cessna Caravan was climbing VFR to 13;500 for OTAY jump zone just north of the B757-200's route. The C-130 was VFR level at 13;000; heading westbound to the TRIDENT jump zone south of the B757-200's flight path. If you don't climb above the jump plane going into OTAY; you have to vector the aircraft around the jump zone because the SID routing is near the southern edge of the jump zone. The TRIDENT jump zone is approximately 2 miles south of the SID routing and the jump planes are generally never a factor. I was worried about the B757-200's rate of climb; because the Caravan was climbing at the same rate. I stopped the Caravan's climb at 11;700 and verified that the B757-200 was climbing through 12;500 to ensure separation. I switched the B757-200 to Center and instead of responding with the frequency; the pilot stated that they were descending because of an RA. As he said this; I realized that the C-130 had turned northbound from the TRIDENT jump zone (level at 13;000 VFR). I told the C-130 to turn right heading 090 immediately. Once the B757-200 was clear of the C-130; the B757-200 was level at 12;000. The Caravan was at the B757-200's 11 o'clock flying northbound and I told the Caravan to continue northbound for traffic. I knew the B757-200 would pass south of the Caravan and had him climb back to 14;000; then FL230. I think I had only worked 30 minutes total and it wasn't busy. I'm so disappointed in myself for not restricting the C-130 to a heading and that I didn't notice the C-130's route of flight before switching the B757-200. It makes you feel bad when an airplane is responding to an RA that you could have prevented. How could I have let that happen and be so confident about the C-130's route of flight? One heading and nothing would have happened. I have worked C-130s in that jump zone before and every time they have flown through the jump zone; gone westbound a few miles then turned back to the east. I should never have assumed that this C-130 would do the same thing. I'm always really vigilant about the north jump zone; because the aircraft working that area always climb high and generally always conflict with the airliners on the departure. I never issued traffic to the C-130 about the B757-200; or the B757-200 about the C-130. I just told the B757-200 about the Caravan because the Caravan was directly in his path. I should never have assumed that the C-130 was going to stay on course but I had given him no instructions. Recommendation; the only thing I can recommend for myself is to never assume what's going to happen. It doesn't make sense to me that I would assume he would fly through the jump zone; even though they typically always do that; but his altitude should have been a big red flag for me. I should have ensured that the B757-200 was above both aircraft before trying to give him a frequency change and I should have ensured the C-130's heading and given each other traffic advisories. I'm generally always giving VFR aircraft headings or instructions to keep them away from other aircraft so the fact that I didn't this time still baffles me. All I can do is thank the pilots for their immediate responses.

Data retrieved from NASA's ASRS site as of July 2013 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.