Narrative:

I was working sectors 45 and 46 combined at sector 46. Aircraft X was on frequency and descending via the MYBAD2 arrival into rno. Aircraft Y was also on frequency at FL200 proceeding direct sgd. As aircraft X descended through FL220; the pilot requested a destination change to smf. My first course of action was to stop aircraft X's descent to remain in my area of jurisdiction so I stopped aircraft X at FL200. I then issued a clearance to smf to aircraft X 'direct moegl; mike oscar echo golf lima; and the remainder of the SLMMR2 arrival; maintain FL200.' the pilot garbled the readback and asked for clarification so I repeated the clearance and reinforced to maintain FL200; not to descend via. The pilot readback moegl SLMMR2 arrival. Shortly thereafter I asked the pilot for the reason for the change of destination. As he finished; I noticed that aircraft X had turned hard left towards aircraft Y and that conflict alert had activated. I immediately turned aircraft X to a 250 heading. Aircraft were getting closer so I climbed aircraft X to FL210 and attempted three times to turn aircraft Y 30 degrees left. Apparently separation was lost; (4.97 mi). After separation was restored I recleared both aircraft on course.I'm not really sure. I think the aircraft; after pilot loaded the SLMMR2 in the computer; started a turn to mdows; the first fix on the arrival from the northeast. Direct moegl would've worked fine. Also if the pilot took his 30 degree left turn immediately and not asked for clarification; separation could've been maintained.

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Original NASA ASRS Text

Title: An Oakland Center (ZOA) Controller reports of a loss of separation due to an aircraft taking a different heading then they were supposed to. A Pilot reports of entering information into the FMS and then aircraft turned to continue on the routing assigned.

Narrative: I was working Sectors 45 and 46 combined at Sector 46. Aircraft X was on frequency and descending via the MYBAD2 arrival into RNO. Aircraft Y was also on frequency at FL200 proceeding direct SGD. As Aircraft X descended through FL220; the pilot requested a destination change to SMF. My first course of action was to stop Aircraft X's descent to remain in my area of jurisdiction so I stopped Aircraft X at FL200. I then issued a clearance to SMF to Aircraft X 'direct MOEGL; Mike Oscar Echo Golf Lima; and the remainder of the SLMMR2 arrival; maintain FL200.' The pilot garbled the readback and asked for clarification so I repeated the clearance and reinforced to maintain FL200; not to descend via. The pilot readback MOEGL SLMMR2 arrival. Shortly thereafter I asked the pilot for the reason for the change of destination. As he finished; I noticed that Aircraft X had turned hard left towards Aircraft Y and that conflict alert had activated. I immediately turned Aircraft X to a 250 heading. Aircraft were getting closer so I climbed Aircraft X to FL210 and attempted three times to turn Aircraft Y 30 degrees left. Apparently separation was lost; (4.97 mi). After separation was restored I recleared both aircraft on course.I'm not really sure. I think the aircraft; after pilot loaded the SLMMR2 in the computer; started a turn to MDOWS; the first fix on the arrival from the northeast. Direct MOEGL would've worked fine. Also if the pilot took his 30 degree left turn immediately and not asked for clarification; separation could've been maintained.

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.