Incident at 80 W. of Fort McMurray, AB (Conflict - loss of separation)

Summary

1997-08-01: UAL 9308, a DC-10, was enroute from Anchorage to Chicago at FL 330, and NWA, a B747F was enroute from Detroit to Narita, Japan at the same altitude. The controller who was handling the two a/c was providing radar separation on parallel tracks, however, an operating irregularity occurred when the crew of UAL 9308 turned right, toward NWA 11. The crews of both a/c initiated evasive action - NWA 11 began a descent and UAL 9308 climbed. At the closest point, the two a/c were one mile and 1500 feet, which is less that the required separation of 5 miles laterally or 2000 feet vertically. At the time of the incident, a/c in that area had been vectored to avoid thunderstorm activity and had the required separation. Once away from the weather, NWA 11 was cleared direct to Fort Nelson and UAL 9308 direct to The Pas. About 2 minutes later, UAL 9308 turned approximately 40-50 degrees to the right, which resulted in the loss of separation. NWA 11 had visual contact with the other a/c and descended, and the audio tapes of NWA 11's radio transmissions indicate the TCAS aural warning in the cockpit. Shortly after, UAL 9308 began a climb to increase separation. Upon questioning, the UAL crew eventually admitted that they "entered the wrong co-ordinates" into their autopliot. Once separation was re-established, the two a/c returned to their assigned altitudes of FL 330. TSB have been advised and will investigate.

Details


CADORS Number 1997C0501
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 1997-07-29 - 22:55
Day or Night? Day-time
Fatalities 0
Injuries
Aerodrome ID
Aerodrome Name
Geographic Location Alberta, Canada, North America, Prairie and Northern Region, 80 W. of Fort McMurray, AB
TSB Occurrence Number
TSB Class of Investigation
AOR Number
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions
Events Conflict - loss of separation


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