Incident at 100 Miles East of Winnipeg, Manitoba (ATS operating irregularity)


1996-09-18: Air Canada ACA181, DC9, enroute from Ottawa to Winnipeg via North Bay direct Sioux Narrows, was at FL350 estimated over Sioux Narrows at 0114Z. This aircraft was on radar vectors to avoid parallel westbound traffic, Canadian CDN935, B737, from Toronto to Winnipeg, was also at FL350. A third aircraft PAC148, a B747 was enroute from Anchorage to Chicago via HANFO Intersection direct Duluth, estimated abeam Sioux Narrows at 0120Z FL330. The flight paths for ACA181 and PAC148 crossed approximately 20 miles west of Sioux Narrows. This cross point is in the Dryden sector's area of responsibility about 10 miles east of the boundry between Winnipeg east sector and the Dryden sector. At 0112Z PAC148 was handed off from Winnipeg east to Dryden. Moments later ACA181 and CDN935 were handed off from Dryden to Winnipeg East. Each aircraft established contact with the new sector and was radar identified. At 0116Z ACA181 requested descent from Winnipeg East and was cleared to FL240. The pilot reported leaving FL350. ACA181 was still in Dryden sector's area of responsibility at the time. A request for early transfer of control on ACA181 had not been made by Winnipeg East. At 0118Z ACA181 reported a TCAS indication and inquired about the traffic that just went by on his right side. Radar data analysis revealed that ACA181 was through FL311 when lateral separation deteriorated to 4.96 miles. Four seconds later lateral spacing was 4.84 miles and ACA181 was through FL308. Lateral spacing began increasing at this point. There was no indication PAC148 was aware of the situation.


CADORS Number 1996C0388
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 1996-09-14 - 01:18
Day or Night?
Fatalities 0
Aerodrome ID
Aerodrome Name
Geographic Location Manitoba, Canada, North America, Prairie and Northern Region, 100 Miles East of Winnipeg, Manitoba
TSB Occurrence Number
TSB Class of Investigation
AOR Number
Reported By NAV CANADA
Categories ATM/CNS
Events ATS operating irregularity

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