Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 18
Confusion
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Equipment / Tooling
I was conducting OJT at the time of the incident; and plugged in for almost 90 minutes. Complexity and volume were high but the sector was kept under control. Aircraft Y was originally climbed to FL150; 1;000 FT below Aircraft X who was level at FL160. After analyzing; my trainee climbed Aircraft Y to FL230. Both aircraft were in a 3 mile area; and I was comfortable with his decision. Aircraft Y was assigned a speed of 300 KTS for in trail spacing on the CSHEL SID. As the aircraft got closer; and converging; I noticed that Aircraft Y's speed had slightly increased and instructed my trainee to turn him 20 degrees right to ensure 3 mile separation. My trainee also expedited the descent of Aircraft X. According to conflict alert which had activated at the sector; closest proximity was 4.093 miles; which I had written down for training debrief. Aircraft Y was then turned back to LAL and we carried on. We were made aware of a loss when I returned to work this afternoon. I immediately requested to go look at the situation on FALCON since I did remember it; and had also written own the CA mileage of 4.093. We reviewed FALCON and verified closest proximity of 4.0! I informed my Supervisor and then had our OM look at it; same thing; no loss; and 4.0 in a 3 mile area. We then proceeded upstairs to QA. QA pulled up the situation on FALCON3; and not the FALCON2 which is available downstairs to us. FALCON3 showed a loss at 2.98 miles. How is it that I am working radar; observe conflict alert closest proximity at 4.093; and not think twice about it; and then come back to work and find out it was 2.98? Am I to trust the mileage I observe and use everyday on my display? How is the data different on my display; FALCON2; and then FALCON3?Use 6 miles since I cannot trust what I see on my display.
On the above date and time; I was working as the Radar Controller (Trainee) at R67/66 while combined [It should be noted that we are still operating on HOST and not ERAM]. We had a stream of departures from RSW with speed restrictions in place to keep them laterally in trail; as well as a string of RSW arrivals on the SHIFTY2 arrival; assorted other traffic; and Aircraft X on the DEAKK Arrival. We had been plugged in to the position since awhile and later got relieved from the position; after the push of departure traffic. I saw Aircraft X on the DEAKK arrival direct DEAKK; which is not uncommon from the 46/47 sectors; depending on their traffic flow. When an aircraft is direct DEAKK; it cuts them across our departure traffic about 20 miles north of where they would be if they were on the full arrival. Likewise; it sometimes puts them in conflict with SHFTY arrivals. I had to maneuver numerous aircraft on the SHFTY and otherwise start them descending before normally doing so; as Aircraft X was coming across that corridor. Likewise; because Aircraft X was direct DEAKK; it cuts him across the departure flow as well; farther north than usual. I had a string of approximately 4-5 departures from my recollection that were all on the CSHEL departure. I issued speeds to keep them laterally sequenced. Aircraft Y was in trail behind another aircraft on the departure; and was issued 300 KTS speed restriction. When he climbed through 10;000 and started accelerating; my trainer; (also a submitter of a separate report) began to discuss the speed restriction and how Aircraft Y accelerating to 300 KTS may not actually mean he will stay behind Aircraft X. Because of this; I had initially climbed Aircraft Y to 15;000 while Aircraft X was level at 16;000. This ensured I had vertical separation until I could further evaluate the situation. After running out the vector lines to assess the situation; (this was while Aircraft Y was at 315 KTS or so glideslope); I believed that I had lateral separation so I discontinued vertical separation. I also knew that I was inside the 3 mile area. I gave the Aircraft X a crossing restriction of DEAKK at 11;000 and 250 KTS; knowing their typical aircraft performance; they would begin a descent and then a speed reduction just prior to the fix. Aircraft Y was through approximately 13;000 for 15;000 and I climbed him to FL230. I also knew that he was a generally slow climbing aircraft; but based on the previous altitude MODE C hits; I knew his climb rate and projected him to be behind and above Aircraft X. When Aircraft Y continued his climb; he also picked up a significant ground speed increase of approximately 30-40 KTS. Because of this change; I turned Aircraft Y twenty degrees right of course to ensure that we still had 3 miles laterally while Aircraft X was level. My vector lines; histories and MODE C reports all indicated that I would have lateral separation; but due to the closing rate; I wanted to ensure that I also had vertical separation; so I asked the Aircraft X to expedite his descent for traffic. He asked me to repeat this transmission; and I did; and also called the traffic to him. I asked Aircraft Y to 'report leaving 16;000'; again; as a second form of separation. I actually turned to my trainer and said 'I guess I really didn't need the altitude report. It looks good.' My trainer observed the conflict alert activate and reduce to 4.093 miles; before increasing. I also concur with this. I observed the closest point that they came on the radar display to be 4.00 miles; and believe I used the RNG BNG function to measure this. I'm not sure if I did on this occurrence; but I usually also switch over to DARC to verify the MODE C hits; if they are indeed close; because sometimes DARC receives faster updates than HOST. I knew I was in a 3 mile area and had the lateral separation required.Upon returning to work; I was informed by my supervisor that I had only 2.98 miles and it was recorded as a loss. I read all the paperwork; which was an email. It also detailed the event. Upon review of the event on FALCON 2 on a ZMA Computer; my instructor and myself observed the closest the two aircraft got were 4.00 miles and 800 FT. Then they began to separate. We; [were] perplexed by this; went to the watch desk and our Supervisor watched the situation on FALCON 2 at the watch desk with the Operations Manager present. They both agreed that we had only 4 miles and 800 FT; but that it was a 3 mile area; so we had no loss. Upon hearing this; we called QA and asked him to explain the situation with us. He said he remembered the event and that he said when he observed it on FALCON 2 it wasn't a loss; but when he went to FALCON 3; he played the event and the closest it got was 3.89 miles; and 800 FT; before increasing. But he then paused the play back; and went frame by frame backwards. While the tracks didn't move; the data block altitude updated and the distances changed. I'm not sure if this is interpolated data; but it wasn't available to us either on the control floor or on FALCON 2. My main concern is if FALCON 3 is being used to report loss events; how come our HOST system doesn't match up with what FALCON 3 is saying? My instructor also kept saying that FALCON 3 was not released to en route facilities; but that it was he used to validate our separation data. Also; is FALCON 3 configured to use the correct radar sort boxes and site? Because of the 3 mile area; it would have to be through the radar sort box of Fort Green; which if the two aircraft were on FALCON 3 at different radar sites; their positions may vary slightly.Also; why is the system that the safety office is using different from what we; as controllers; have access to and can review our sessions with? When I walked out of the control room; there was no doubt in my mind that I had 4 miles and it was no issue; but now I am beginning to question that. If this situation we had less than 3 miles; what other situations in which I've used 3 miles the FALCON 3 reports we had less than that?While this sector continues to be extremely complex; I think you'll continue to see a string of separation and airspace violations due to the outdated layout of the South Florida Airspace system; but I'm not sure what could be done to improve it without a complete redesign.
Two Controllers report of finding out about a loss of separation after returning to work. Two different types of replay instruments were used and one showed a loss of separation; while the other did not.