Date: 201512
Local time of day: 0001-0600
Location: ZLA.ARTCC, CA
Aircraft: Light Transport
Operator: Air Carrier
Operating under: Part 91
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZLA
ATC / advisory: Center ZLA
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Human-Machine Interface; Situational Awareness; Training / Qualification
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic; Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Contributing factors: Procedure; Airspace Structure; Human Factors
Primary problem: Procedure

Narrative: I was training a safety event involving a SID and STAR occurred. [AIRCRAFT X] was [destined for] HND via the NOOTN1 direct SHABI descending to FL240 with track control and communications given to the sector below us ZLA sector 07. The aircraft in the opposite direction [of] [AIRCRAFT Y] a LAS departure was on the TRALR departure BCE transition climbing to FL230 in a handoff status from sector 07 to sector 33. In this circumstance the controlling team at sector 07 would decide if the aircraft can out climb and out dive each other or if they needed to assign a heading with their departure and their arrival aircraft. We accepted the Handoff on [AIRCRAFT Y] and assigned the climb to FL290 assuming that the sector 07 controller was going to dive [AIRCRAFT X] below the [AIRCRAFT Y] departure. A minute went by and we did not notice a steep enough descent rate for adequate separation from [AIRCRAFT X] and [AIRCRAFT Y]. Our R-side issued a turn to the east of a 055 heading which allow[ed] the 07 controller to issue [AIRCRAFT X] a direct routing westbound to MORRK. At this point [AIRCRAFT X] was inside 07 airspace at FL230 and descending while [AIRCRAFT Y] was climbing out of FL190 while also in sector 07 airspace. After we issued a 055 heading; we noticed sector 07 updated their data tag to read 20L which would put the aircraft back on collision course with [AIRCRAFT Y]. Shortly after we notice[d] the data tag change D07 calls D33 instructing D33 to stop [AIRCRAFT Y] at FL210. [AIRCRAFT Y] mode C indicated was FL205 and climbing. I keyed up over my D-side trainee and said the [AIRCRAFT Y] is already FL210. Then R07 called up D33 shouted to stop [AIRCRAFT Y] at FL210 and the data tag in [AIRCRAFT X] indicated an Interim altitude of FL220. This was not going to stop the aircraft from colliding and was poor plan. I told the R-side what control instruction [were] issued to me by R&D 07. R33 took abrupt action and expedited [AIRCRAFT Y] to climb and then called R07 and instructed them to issue and expedited descent clearance to Aircraft X. At the end of the event no separation was lost. The first key problem is a SID and a STAR is head on with each other. The second issue is the sector of control did not notice a conflicting route.The third issue is when the low sector turned their westbound arrival away from the airport and inadvertently turned the aircraft into the east bound departure. The fourth issue is misinterpreting radar lag and issuing an altitude clearance to high sector where the aircraft in concern has most likely passed through the newly assigned altitude.




Synopsis: ZLA handoffs between a low sector and a high sector cause issue as two aircraft; one departing LAS and one arriving HND come in conflict. There was miscommunication between the two sectors as to who and how the two aircraft would be separated. Separation was never lost due to drastic last minute control instructions.