Incident at ST. JOHN'S INTL NL (CYYT) (Conflict - loss of separation, ATS operating irregularity)


2003-03-05: TSB - Update - A03A0027: AMX005, an Air Mexico B-767 was en route from Mexico City, Mexico to Paris, France crossing 46N/50W at 0234 UTC, estimating 48N/40W at 0319 UTC at FL380. COA34, a Continental Airlines B-777 was en route from Houston, Texas to London, England crossing 46N50W at 0241 UTC, estimating 48N/40W at 0329 UTC at FL039. At 0243 UTC, AMX005 requested FL390. The controller completed a trial probe to determine if separation would be maintained between the aircraft. The controller then cleared AMX0005 to FL390 at which time separation between the aircraft eroded to approximately 7 minutes longitudinally where 10 minutes longitudinal or 1000 feet vertical is required. By the time the error was discovered, required separation had been regained. The method the controller used for the trial probe is for use in a radar controlled environment by flight planners prior to the aircraft entering oceanic airspace. Included in this method is a sliding Mach scale which is used when the leading aircraft is faster thus assuring separation as both aircraft progress. This allows the aircraft to enter oceanic airspace without the required 10 minute longitudinal separation. The incident aircraft were already in oceanic airspace where other methods of determining separation should be used by controllers. Nav Canada is convening an Operational Safety Investigation.
2003-02-20: A Boeing 767 enroute from Mexico to Charles de Gaulle (AMX005) was cleared from Flight Level 380 to Flight Level 390 with less than the required separation from COA34 which was operating at Flight Level 390. COA34 was a Boeing 777 enroute from Houston to Gatwick.


CADORS Number 2003A0117
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2003-02-19 - 02:47
Day or Night?
Fatalities 0
Aerodrome ID CYYT
Aerodrome Name ST. JOHN'S INTL NL (CYYT)
Geographic Location Newfoundland and Labrador, Canada, North America, Atlantic Region, Approximately 40 NM East of 46N 50W
TSB Occurrence Number
TSB Class of Investigation
AOR Number 27701
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions,ATM/CNS
Events Conflict - loss of separation,ATS operating irregularity

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