Date: 201503
Local time of day: 1201-1800
Location: ZMA.ARTCC, FL
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZMA
ATC / advisory: Center ZMA
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Situational Awareness
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Contributing factors: Procedure; Human Factors; Staffing
Primary problem: Procedure

Narrative: I was working sector R64 by myself during a busy afternoon push.  The AVON high and placid MOA's had gone active and traffic was starting to bottle neck around the vicinity of the LBV VOR as it always does when those areas go active.  R47 was feeding me departures from the low side and had assigned speeds to aircraft X and aircraft Y from the low side.  R47 called me on the override and requested higher altitude on aircraft X who had a speed assigned of 310 knots+ and was in front of aircraft Y.  I approved FL320 on aircraft X.  Aircraft Y who was in trail checked on my frequency with a speed assigned FL280 in fourth line data block and I climbed to FL340.  I initiated an automated handoff on both aircraft to sector R25 and after they accepted the handoffs I shipped them both to them.  I was doing other R side things with other aircraft in my sector when I then notice the conflict alert going off between aircraft X and aircraft Y; who R25 had control of at the time; and tried to steady the conflict alert.  That's when I noticed that both aircraft had the speeds removed from the 4th line in the data block; aircraft X was at FL320 and aircraft Y was over taking him from behind and was out of FL323 or so and was not able to stop the conflict alert because a loss of separation was happening.  March is our busiest traffic volume month of the year.  We are constantly going into shifts short handed and today was no exception.  I mentioned to the Front Line Manager (FLM) on duty that we did not have enough controllers to man D-sides and to open all our sectors like we had in the past.  The traffic was not being flowed sufficiently for sectors that were being one armed and with military areas active that were adding complexity to the area.  My suggestion would be that sectors be split and D-sides be available in a timely manner during our busiest time of the year.  Traffic needs to be flowed more efficiently; especially when the military activates the MOA's that greatly restrict our airspace.  I am not alone in my area when I say we are constantly working sectors by ourselves and when we do ask for a D-side and get one; we are then pressured to going back to one arming the sector because that D-side controller is usually the only D-side available in the area and someone else is also in need of a D-side.  We are working overtime all the time both assigned and hold over and the staffing situation doesn't seem to be getting better.  I've been in the everglades area for years now and this is by far the worse staffing levels I have ever seen.  We have seven sectors in our area of specialization and we are constantly going into shifts with seven or eight controllers.  Barely enough to work 4 sectors let alone open all seven and staff D-sides and ensure we get breaks moving.




Synopsis: A Miami Center (ZMA) Controller reports of a loss of separation with two aircraft after he handed them off and transferred communications to another sector. Someone had removed the assigned speeds from the data block indicating normal speed had been given; resulting in a loss and an aircraft was climbed through the others altitude.