Date: 201701
Local time of day: 0601-1200
Location: ZLA.ARTCC, CA
Light: Daylight
Aircraft: Small Transport; Low Wing; 2 Turbojet Eng
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZLA
ATC / advisory: Center ZLA
Second aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Fatigue; Situational Awareness; Workload; Communication Breakdown
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance
Contributing factors: Company Policy; Human Factors; Procedure; Staffing
Primary problem: Procedure

Narrative: While working Sector 27 the CIC came over and advised me that TMU (Traffic Management Unit) called and said it looked like I may be going over MAP (Monitor Alert Parameters) numbers. As it turned out I was already over the numbers by 20 percent; split roughly equally between arrival; departure; and enroute traffic. The D-side was saturated with landline calls and we really needed an overhead; but everyone else was one-holing thus nobody was available. I had several upside-down stacks; several arrivals that were tied; and ZOA13 wasn't complying with the LOA; SF Bay area departures landing ONT/PSP need to be capped at 370; but I got one at 410 on top of an enroute. As far as the incident aircraft are concerned; I had Aircraft X #1 in a string of 3 arrivals that I needed to get down so I could get under my departures in order to S-turn him and make him #3. I descended him to 31000 noting that Aircraft Y was converging at 32000; but 60 miles away. I assumed Aircraft X would descend at 1000 fpm and thus wouldn't be a factor. I shifted my attention to all the other issues I still had to work out and didn't notice Aircraft X was floating it down until he was through 32900 and passed Aircraft Y. I keyed up intending to level him at 330; but realized it was already too late. Conflict alert never went off; nor did the (now) FLM or D-side notice until I did.The timely issuance of TMIs (Traffic Management Initiatives) would have helped tremendously with this session. It seems to me too often TMU simply calls to warn us were going over numbers instead of instituting flow restrictions. The routine recently has been to staff the shifts anywhere from 1-3 below guidelines with the overtime list completely exhausted. As a result we've had positions combined much more than I feel is safe. Our ARMOR playbook notes what TMIs should go into place for various diminished staffing levels; but I don't know whether it was actually being followed.I should also note that we've been on mandatory 6-day weeks for about 8 months now; and I had been working weekly over-time on a voluntary basis for over a year prior. I have noticed recently that I have a harder time focusing now than when we'd only get 1 or 2 overtimes a month. I know the fatigue MOU (Memorandum of Understanding) allows me to take leave if I need the time to rest; but our shifts are staffed so badly that I can't use the leave without adversely affecting the system and my colleagues. Plus; I imagine they'd see taking a 'fatigue day' once every other week as abusive. I suppose I could use some clarification on the application of leave in accordance with the fatigue MOU.

Callback: Reporter stated that ARMOR is a facility only Traffic Management Acronym that is in place for specifics of what to do to help a sector when one is combined. Reporter stated they do not know what the term actually stands for.



Synopsis: ZLA ARTCC Controller reported a loss of separation due to an aircraft not descending as fast as the Controller assumed it would.