Narrative:

Aircraft #1 was a vny departure eastbound over pmd climbing to FL190. Aircraft #2 was a bur arrival at FL200 cleared to cross 10 mi east of pmd at 14000 ft. Aircraft #1 was waiting to clear an ont arrival over pmd that was descending to FL200. When aircraft #1 was clear of the crossing traffic was ready to climb I noticed aircraft #2 hadn't started his descent yet. I cleared aircraft #2 to amend his altitude and maintain FL200 and called the traffic. The readback was unclr and only a partial call sign of aircraft #2. In the middle of reissuing the clearance; I noticed aircraft #2 had left FL200 and was diving to make his crossing restr. I issued aircraft #2 to expedite through FL180 to maintain 14000 ft and issued aircraft #1 to climb and maintain FL210. Aircraft #2 advised he was responding to an RA and was climbing. I turned aircraft #2 40 degrees left and turned aircraft #1 20 degrees left. There were some contributing factors to the error. Aircraft #1 was climbing out at 265 KTS. 8 mi behind him was an A320 climbing at over 300 KTS. I issued a speed to the A320 and aircraft #1 read the clearance back. This forced me to reissue the clrncs. A CRJ2 was over pmd at 14000 ft and had not descended into approach control airspace. Approach called and requested communication with the CRJ2. I had already issued the frequency change to the pilot and I reissued the clearance. The crj read the clearance back once more. The CRJ2 didn't start his descent for about 45 more seconds. This required a pointout to another sector. I also had traffic slowly climbing out of 12000 ft for 15000 ft head-on with the CRJ2. An aircraft checked on my frequency level at FL370 that I didn't have track control of. I located the aircraft and issued him the correct frequency. These all added to workload and complexity at the sector.

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Original NASA ASRS Text

Title: ZLA CTLR LOSES SEPARATION AT APPROX FL200 DURING CROSSOVER BTWN ARR AND DEP ACFT WHEN SEVERAL XMISSIONS WERE CONFUSED.

Narrative: ACFT #1 WAS A VNY DEP EBOUND OVER PMD CLBING TO FL190. ACFT #2 WAS A BUR ARR AT FL200 CLRED TO CROSS 10 MI E OF PMD AT 14000 FT. ACFT #1 WAS WAITING TO CLR AN ONT ARR OVER PMD THAT WAS DSNDING TO FL200. WHEN ACFT #1 WAS CLR OF THE XING TFC WAS READY TO CLB I NOTICED ACFT #2 HADN'T STARTED HIS DSCNT YET. I CLRED ACFT #2 TO AMEND HIS ALT AND MAINTAIN FL200 AND CALLED THE TFC. THE READBACK WAS UNCLR AND ONLY A PARTIAL CALL SIGN OF ACFT #2. IN THE MIDDLE OF REISSUING THE CLRNC; I NOTICED ACFT #2 HAD LEFT FL200 AND WAS DIVING TO MAKE HIS XING RESTR. I ISSUED ACFT #2 TO EXPEDITE THROUGH FL180 TO MAINTAIN 14000 FT AND ISSUED ACFT #1 TO CLB AND MAINTAIN FL210. ACFT #2 ADVISED HE WAS RESPONDING TO AN RA AND WAS CLBING. I TURNED ACFT #2 40 DEGS L AND TURNED ACFT #1 20 DEGS L. THERE WERE SOME CONTRIBUTING FACTORS TO THE ERROR. ACFT #1 WAS CLBING OUT AT 265 KTS. 8 MI BEHIND HIM WAS AN A320 CLBING AT OVER 300 KTS. I ISSUED A SPD TO THE A320 AND ACFT #1 READ THE CLRNC BACK. THIS FORCED ME TO REISSUE THE CLRNCS. A CRJ2 WAS OVER PMD AT 14000 FT AND HAD NOT DSNDED INTO APCH CTL AIRSPACE. APCH CALLED AND REQUESTED COM WITH THE CRJ2. I HAD ALREADY ISSUED THE FREQ CHANGE TO THE PLT AND I REISSUED THE CLRNC. THE CRJ READ THE CLRNC BACK ONCE MORE. THE CRJ2 DIDN'T START HIS DSCNT FOR ABOUT 45 MORE SECONDS. THIS REQUIRED A POINTOUT TO ANOTHER SECTOR. I ALSO HAD TFC SLOWLY CLBING OUT OF 12000 FT FOR 15000 FT HEAD-ON WITH THE CRJ2. AN ACFT CHKED ON MY FREQ LEVEL AT FL370 THAT I DIDN'T HAVE TRACK CTL OF. I LOCATED THE ACFT AND ISSUED HIM THE CORRECT FREQ. THESE ALL ADDED TO WORKLOAD AND COMPLEXITY AT THE SECTOR.

Data retrieved from NASA's ASRS site as of January 2009 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.