Narrative:

On departure out of las, departure gave us 7000 ft on the oveta 3. We were to maintain 7000 ft for traffic behind us which would be a conflict once we turned towards the boulder city VOR. About 1/2 way through the turn, we noticed another TCASII aircraft below us (500 ft on TCASII). We were level at 7000 ft trying to get a visual on both the lower traffic (by departure) at 2 O'clock position. While still in the turn through north, we got an RA to climb. I (the first officer) initiated a climb up to 7300 ft to avoid the lower conflict, but didn't want to go higher until I could see the traffic at 7500 ft. At 7300 ft I picked up the 7500 ft VFR traffic and the RA was resolved. I descended back to 7000 ft once the lower traffic went behind us. The cessna had started a 360 degree turn to avoid the area and we continued out on a 080 degree heading to resume the departure. I don't believe departure ever had the lower altitude traffic on radar, since they never called them out. When the captain advised them we were climbing, they wanted us to descend because of the other higher. We never saw the lower aircraft, we think we passed within 2 mi and 300 ft of it. The higher aircraft we passed 2 mi and 500 ft. The only solution we saw would've been for us to roll out on a nnw heading to avoid the area altogether. However, I don't know if that would've helped with the ATC or the unknown traffic since we never saw it to get a good feel for its heading. Supplemental information from acn 523446: we were layered between 2 VFR GA aircraft. Both were being tracked by departure. The fact that departure had not called the 6500 ft traffic prior to the RA did not give me much time to scan before responding to the RA. We were both aware of the 6500 ft (climbing indicated on TCASII) and 7500 ft (level indicated) traffic. It was an uncomfortable but manageable situation. Departure was very neutral, neither helpful nor hurtful, in the situation. The turn by the 7500 ft traffic, when he had us in sight, aided in mitigating the situation.

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Original NASA ASRS Text

Title: B737 FLC TAKE ACTION DUE TO A TCASII RA FROM KNOWN AND A SECOND UNKNOWN ACFT PASSING IN THEIR VICINITY WHEN EXECUTING THE OVETA SID FROM LAS.

Narrative: ON DEP OUT OF LAS, DEP GAVE US 7000 FT ON THE OVETA 3. WE WERE TO MAINTAIN 7000 FT FOR TFC BEHIND US WHICH WOULD BE A CONFLICT ONCE WE TURNED TOWARDS THE BOULDER CITY VOR. ABOUT 1/2 WAY THROUGH THE TURN, WE NOTICED ANOTHER TCASII ACFT BELOW US (500 FT ON TCASII). WE WERE LEVEL AT 7000 FT TRYING TO GET A VISUAL ON BOTH THE LOWER TFC (BY DEP) AT 2 O'CLOCK POS. WHILE STILL IN THE TURN THROUGH N, WE GOT AN RA TO CLB. I (THE FO) INITIATED A CLB UP TO 7300 FT TO AVOID THE LOWER CONFLICT, BUT DIDN'T WANT TO GO HIGHER UNTIL I COULD SEE THE TFC AT 7500 FT. AT 7300 FT I PICKED UP THE 7500 FT VFR TFC AND THE RA WAS RESOLVED. I DSNDED BACK TO 7000 FT ONCE THE LOWER TFC WENT BEHIND US. THE CESSNA HAD STARTED A 360 DEG TURN TO AVOID THE AREA AND WE CONTINUED OUT ON A 080 DEG HDG TO RESUME THE DEP. I DON'T BELIEVE DEP EVER HAD THE LOWER ALT TFC ON RADAR, SINCE THEY NEVER CALLED THEM OUT. WHEN THE CAPT ADVISED THEM WE WERE CLBING, THEY WANTED US TO DSND BECAUSE OF THE OTHER HIGHER. WE NEVER SAW THE LOWER ACFT, WE THINK WE PASSED WITHIN 2 MI AND 300 FT OF IT. THE HIGHER ACFT WE PASSED 2 MI AND 500 FT. THE ONLY SOLUTION WE SAW WOULD'VE BEEN FOR US TO ROLL OUT ON A NNW HDG TO AVOID THE AREA ALTOGETHER. HOWEVER, I DON'T KNOW IF THAT WOULD'VE HELPED WITH THE ATC OR THE UNKNOWN TFC SINCE WE NEVER SAW IT TO GET A GOOD FEEL FOR ITS HDG. SUPPLEMENTAL INFO FROM ACN 523446: WE WERE LAYERED BTWN 2 VFR GA ACFT. BOTH WERE BEING TRACKED BY DEP. THE FACT THAT DEP HAD NOT CALLED THE 6500 FT TFC PRIOR TO THE RA DID NOT GIVE ME MUCH TIME TO SCAN BEFORE RESPONDING TO THE RA. WE WERE BOTH AWARE OF THE 6500 FT (CLBING INDICATED ON TCASII) AND 7500 FT (LEVEL INDICATED) TFC. IT WAS AN UNCOMFORTABLE BUT MANAGEABLE SIT. DEP WAS VERY NEUTRAL, NEITHER HELPFUL NOR HURTFUL, IN THE SIT. THE TURN BY THE 7500 FT TFC, WHEN HE HAD US IN SIGHT, AIDED IN MITIGATING THE SIT.

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.