On 20 July 1998, after an ATC error south of Newfoundland, an Air France A340 Family and an Air Canada 747-400 were on directly converging tracks and at the same level. Collision was avoided by the correct actioning of coordinated Airborne Collision Avoidance System (ACAS) RAs by both aircraft.
The following is extracted from the synopsis of the official Transport Safety Board (Canada)Report:
"Air France flight 033 (AFR033), an Airbus A340 aircraft, was en route from Houston, Texas, USA, to Paris, France, at flight level FL370 with a routing of WHALE, BANCS, and latitude 46N longitude 50W (Oceanic Track "X"). Air Canada flight 870 (ACA870), a Boeing B747 aircraft, was en route from Montreal, Quebec, to Paris at FL370 with a routing of MILLS, COLOR, and latitude 47N longitude 50W (Oceanic Track "W"). ACA870 was re-cleared from MILLS direct to latitude 45N longitude 50W (Oceanic Track "Y"). The new routing placed ACA870 on a converging track with AFR033. Approximately 30 miles west of the BANCS intersection, both aircraft received and responded to traffic avoidance and collision advisory system (TCAS) resolution advisories (RA). A loss of separation occurred at approximately 0213 Coordinated Universal Time (UTC) when the two aircraft closed to approximately 400 ft vertically and 1.9 nm horizontally. The required separation in the airspace for these aircraft is 5 nm horizontally or 1000 ft vertically."
Loss of Separation near BANCS