Narrative:

I was working D40; I took a point out on a PC12 level at FL260 from sector 31 cutting through my airspace northwest bound. Due to the large number of departure aircraft that are released into our airspace I kept the PC12 on our display while he was in sector 30's airspace just in case I was going to need to stop aircraft at a safe altitude that may be climbing into his altitude. However after the PC12 was outside of our airspace I did not remove what would have been deadwood. When I first noticed the widebody being handed off to us I saw the issue wondering if sector 30 would eventually stop the aircraft's climb at FL250 for the PC12 traffic. However as I noticed nothing was being accomplished to avoid the problem I told my r-side I was going to call and tell them and make sure they stopped the aircraft at FL250. At the point when I saw the conflict there was time to alleviate the issue because the widebody was barely out of FL230. My r-side decided to take it upon himself and call sector 30 to remind them about their traffic (the PC12) and told them they should stop the widebody at FL250. The d-side at sector 30 took the call and we thought that would be the end of it until we both observed the widebody was still climbing and a 15L turn was issued to him as it displayed in the 4th line of the data block. I and the r-side on sector 40 both agreed the situation was unsafe as we observed the widebody climbing into the PC12's altitude. Our sector was very busy at the time and from what I observed the r-side on sector 30 may have descended the PC12 to get underneath the widebody whom was already at FL250 and climbing. Afterward I observed the widebody descending to FL240 into the PC12's altitude which may have been a result of a RA from his TCAS. All in all I'm not sure what the thought was on not stopping the widebody for the PC12 traffic; but after observing two aircraft fly into close proximity of one another I was fearful for the safety of both aircraft involved.a recommendation is hard to note in this situation because I am unsure as to whether or not the d-side told the r-side to stop the widebody at FL250 or if the r-side working sector 30 did not listen to him. In either case the d-side needed to remind the r-side of the severity of the situation and to take immediate action which may or may not have been accomplished.

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Original NASA ASRS Text

Title: A Heavy aircraft flight crew and a ZLA Controller involved; describe a loss of separation incident between the climbing Heavy and a PC12 level at FL260. The PC12 is apparently issued a descent clearance at about the same time the Heavy crew receives a descend RA. The PC12 pilot is able to out descend the Heavy and passes below it.

Narrative: I was working D40; I took a point out on a PC12 level at FL260 from Sector 31 cutting through my airspace NW bound. Due to the large number of departure aircraft that are released into our airspace I kept the PC12 on our display while he was in Sector 30's airspace just in case I was going to need to stop aircraft at a safe altitude that may be climbing into his altitude. However after the PC12 was outside of our airspace I did not remove what would have been deadwood. When I first noticed the Widebody being handed off to us I saw the issue wondering if Sector 30 would eventually stop the aircraft's climb at FL250 for the PC12 traffic. However as I noticed nothing was being accomplished to avoid the problem I told my R-side I was going to call and tell them and make sure they stopped the aircraft at FL250. At the point when I saw the conflict there was time to alleviate the issue because the Widebody was barely out of FL230. My R-side decided to take it upon himself and call Sector 30 to remind them about their traffic (the PC12) and told them they should stop the Widebody at FL250. The D-side at Sector 30 took the call and we thought that would be the end of it until we both observed the Widebody was still climbing and a 15L turn was issued to him as it displayed in the 4th line of the data block. I and the R-side on Sector 40 both agreed the situation was unsafe as we observed the Widebody climbing into the PC12's altitude. Our Sector was very busy at the time and from what I observed the R-side on Sector 30 may have descended the PC12 to get underneath the Widebody whom was already at FL250 and climbing. Afterward I observed the Widebody descending to FL240 into the PC12's altitude which may have been a result of a RA from his TCAS. All in all I'm not sure what the thought was on not stopping the Widebody for the PC12 traffic; but after observing two aircraft fly into close proximity of one another I was fearful for the safety of both aircraft involved.A recommendation is hard to note in this situation because I am unsure as to whether or not the D-side told the R-side to stop the Widebody at FL250 or if the R-side working Sector 30 did not listen to him. In either case the D-side needed to remind the R-side of the severity of the situation and to take immediate action which may or may not have been accomplished.

Data retrieved from NASA's ASRS site 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.