History of the Flight
Air France flight 033 (AFR033), an Airbus A340, was en route from Houston, Texas, to Paris, France, at flight level 370, following a route of WHALE, BANCS, and latitude 46N longitude 50W (Oceanic Track X). Air Canada flight 870 (ACA870), a Boeing 747, was en route from Montreal, Quebec, to Paris at the same flight level, with an initial routing of MIILS, COLOR, and latitude 47N longitude 50W (Oceanic Track W). ACA870 was re-cleared from MIILS direct to latitude 45N longitude 50W (Oceanic Track Y), placing it on a converging track with AFR033.
The two aircraft were controlled by the Gander Area Control Centre (ACC) high domestic controllers responsible for the combined sector BANCS and south. ACA870, with 265 passengers and a crew of 14, had been issued an amended oceanic clearance prior to handoff to the BANCS radar controller. The aircraft contacted the radar controller at 0151:15 UTC, outside the geographic boundaries of the BANCS sector, and crossed the sector boundary at 0207. ACA870 provided position estimates indicating it was level at FL 370 and estimating latitude 45N longitude 50W at 0227.
AFR033, with 235 passengers and a crew of 14, received an oceanic clearance and was handed off to the radar controller at 0158:32. It was established on the route WHALE direct to BANCS, level at FL 370, and estimating BANCS at 0217. Its track during this portion was approximately 076 magnetic.
Response and TCAS
At approximately 0211, as ACA870 approached 40 nm west of the BANCS intersection en route to latitude 45N longitude 50W, the radar controller contacted ACA870 and advised that radar service would terminate at longitude 50W and to contact Gander radio on frequency 126.9 MHz. At this time, ACA870 was approximately 9 nm from AFR033 and converging on a track of 116 magnetic. No further action was taken by the radar controller.
At 0212:33, while the radar controller was communicating with another aircraft, ACA870 received a TCAS resolution advisory (RA) and attempted to make radio contact but was cut off. Seven seconds later, ACA870 declared Pan, Pan, Pan. The radar controller issued a clearance to descend to FL 360. ACA870 replied that they were climbing as a result of the RA and were on a collision course. The controller advised ACA870 to follow the advisory.
Immediately after, AFR033 declared Pan, Pan, Pan and advised that it was descending due to a TCAS RA. AFR033 received an initial traffic advisory at 0211:34 and an RA to descend at 0212:47. Recorded radar data showed AFR033's altitude at 36,900 feet at 0212:49, 36,700 feet at 0212:54, 36,700 feet at 0212:59, and 36,400 feet at 0213:03. Aircraft data from Air France indicated an altitude of 36,788 feet at 0212:59 with a downward velocity of 1,790 feet per minute, and 36,384 feet at 0213:30. The time between the onset of the RA and initiation of descent with the autopilot off was two seconds.
On receiving the RA, ACA870 began an immediate climb to FL 380, reaching that altitude approximately 50 seconds after commencement. Seventeen seconds after the end of AFR033's Pan transmission, ACA870 advised that they were directly overhead the Air France aircraft and that the two aircraft would have collided.
The loss of separation occurred at approximately 0213 UTC when the two aircraft closed to approximately 400 feet vertically and 1.9 miles horizontally. The required separation in that airspace is 5 miles horizontally or 1000 feet vertically.
Personnel
The BANCS sector was staffed by a data controller and a radar controller. The radar controller had eight years of experience, the data controller nine years. Both were appropriately licensed and qualified. The radar controller had been on duty for six hours, and the data controller for three hours and 45 minutes. The radar controller was on the first shift of his work cycle after two days off. The data controller had worked 16 shifts in the previous 18 days, seven of which were overtime. Traffic volume at the time was described as moderate to heavy. All equipment was serviceable.
Aircraft Information
Air Canada's Boeing 747-400, registration C-GAGN, was powered by four engines. Air France's Airbus A340, registration F-GLZL, was also a four-engine aircraft. No damage occurred to either aircraft.
Other Details
The weather was clear in the vicinity. All navigation aids operated normally. Communications were serviceable.
Flight progress strips for ACA870 were not marked with the required notations to indicate the aircraft would go abeam a fix or to highlight potential radar conflicts, as per the Gander ACC Operations Manual. The data controller was fully occupied with flight data flow and was not aware of the activities on the radar controller's display.