Incident at 200 NM NE of Churchill, MB (ATS operating irregularity)


1999-03-23: AZA 622, an MD-11, was enroute from Milan to Los Angeles at FL 330 and was estimating 62N 90W at 1759Z. UAL 935, a B777, was enroute from Heathrow to Los Angeles at FL 350 with an estimated time for 62N 90W, as provided to Winnipeg ACC by Edmonton ACC, of 1908Z. At 1801Z, the crew of AZA 622 reported at 90W and they were then cleared to FL 350. At 1809Z, one hour earlier than the ETA, the crew of UAL 935 reported at 90W, at which time the Radar and Data Controllers realized that the two a/c were in conflict and the ETA for UAL 935 was not correct. The crew of UAL 935 was cleared to FL 370 to ensure that separation was maintained. A review of the audio tapes confirmed that the estimate for UAL 935 to reach 80W as provided by Edmonton ACC was 1826Z. Further investigation will be conducted by Edmonton ACC. OPI - ANS and Airspace; Enforcement UPDATE TSB reported that it was unlikely the required separation of 10 minutes was lost, however, safety was not assured during the occurrence. 2ND UPDATE ANS and Airspace reported that the occurrence is being looked into by a NavCanada Fact Finding Board.


CADORS Number 1999C0195
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 1999-03-17 - 18:09
Day or Night? Day-time
Fatalities 0
Aerodrome ID
Aerodrome Name
Geographic Location Manitoba, Canada, North America, Prairie and Northern Region, 200 NM NE of Churchill, MB
TSB Occurrence Number
TSB Class of Investigation
AOR Number
Reported By NAV CANADA
Categories ATM/CNS
Events ATS operating irregularity

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