SUMMARY On Thursday, November 11, 2010, at approximately 1731 EST, a Boeing 737-800 operating as Delta Airlines flight 654, and an Airbus A319 operating as Avianca flight 287, were transiting the Miami Air Traffic Control Center Class A airspace on opposite direction crossing courses when the flight crews of both airplanes received Traffic Alert and Collision Avoidance System (TCAS) resolution advisories (RA). DAL654 was traveling northwest at FL370, and AVA287 was traveling southeast climbing from FL360 to FL370. The airplanes were within the confines of ZMA sector 21, but were under the control of two different air traffic controllers. Before the flights passed each other, AVA287 was instructed to climb from FL360 to FL370, placing the flight in direct conflict with DAL654. When the airplanes were approximately 66 nautical miles east of Hobe Sound, Florida, the ZMA radar data processing system generated a conflict alert to the two controllers. At about the same time, the two crews received TCAS RAs. The controllers instructed the two flights to turn, and AVA287 was instructed to climb to FL390. The pilots responded to their TCAS RA commands. The airplanes passed within approximately 1800 feet vertically and 2.81 miles laterally of each other. DAL654 was on a regularly scheduled passenger flight from Queen Beatrix International Airport (TNCA), Oranjestad, Aruba, to Hartsfield - Jackson Atlanta International Airport (ATL), Atlanta, Georgia and was operating under 14 Code of Federal Regulations Part 121. AVA287 was on a regularly scheduled passenger flight from Washington Dulles International Airport (IAD), Washington, DC, to El Dorado International Airport (SKBO), Bogotá, Colombia, and was operating under 14 Code of Federal Air Regulations Part 129. The incident occurred during daytime (dusk) visual meteorological conditions. There was no damage to either aircraft and no reported injuries. HISTORY OF FLIGHT On Thursday, November 11, 2010, at about 1726 EST, DAL654 entered ZMA Sector 21 airspace from the southeast heading northwest at FL370. At about 1727, AVA287 entered ZMA Sector 21airspace from the northwest heading southeast at FL360. DAL654 and AVA287 were on opposite direction crossing courses. At about 1728:09, the Sector 21 radar controller (R21) completed a radar handoff of DAL654 to sector 2, and transferred communications with the flight to the R2 controller. The transfer occurred while DAL654 was well within the confines of the R21 controller’s airspace. Since Sector 21’s airspace was only about 50 miles wide, it was common practice for the R21 controllers to transfer control of airplanes to the next sector controller as soon as possible. No conflicts existed at the time DAL654 was transferred to the R2 controller. Approximately one minute after transferring DAL654 to the R2 controller, and before the flights passed each other, the R21 controller climbed AVA287 from FL360 to FL370, which placed the flight in direct conflict with DAL654. At about 1730:03, as AVA287 climbed through FL366, the R21 and R2 controllers each received a conflict alert. The R21 controller turned AVA287 to heading 090, but four seconds later amended the turn to the right, heading 270. The R2 controller subsequently issued DAL654 a right turn to heading 360. At about 1730:23, the R21 controller instructed AVA287 to “climb and maintain flight level 390, report out of flight level 380 for traffic.” The pilot did not respond. Radar data indicated the distance between the two airplanes was approximately 10 miles laterally and 300 feet vertically; DAL654 was at FL370 and AVA287 was at FL367. About twenty seconds later, the R21 controller transmitted, “AVA287 climb and maintain flight level three (the controller abruptly paused his transmission and did not state the remainder of the altitude assignment before he continued), report out of flight level (unreadable).” The pilot of AVA287 did not respond. At about 1730:31 the pilot of DAL654 reported to the R2 controller that the flight was “descending, we have RA traffic in sight.” This was the only indication to the controllers that a TCAS RA had occurred. The R2 controller advised DAL654, “traffic at your 12’o'clock, 5 miles, turning right to a 270 heading.” At about 1730:48, the R21 controller instructed AVA287 to, “report out of flight level 380.” The pilot read back “flight level 380, AVA287.” Traffic information was not provided to AVA287. At about 1730:49, radar data indicated AVA287 was at FL384 and DAL654 was at FL364. The pilot of DAL654 informed the R2 controller that the flight was, “leveling FL360 and climbing back up to FL370, resuming course direct to Ormond Beach.” The pilot of AVA287 reported the TCAS RA to the subsequent sector controller. Both flights continued to their destinations without further incident. RADAR DATA Radar data for this report was obtained from the Tamiami (ZQM8) ARSR-4 sensor located 17 miles southwest of Miami International Airport, Miami, Florida. A graphic overview of the flight paths of DAL654 and AVA287, and a close-up view of the minimum separation between the two airplanes are contained in ATC Group factual report and have been added to the docket. For further information, see the ATC Group Chairman's Factual Report in the docket for this case.