Incident at WHITEHORSE/ ERIK NIELSEN INTL (CYXY) (Conflict - potential, ATS operating irregularity)


2003-07-14: UPDATE ANS and Airspace reported that Nav Canada will convene an Operational Safety Investigation concerning this occurrence.
2003-03-21: ANT 506 was cleared from FL 320 to FL 200 after it reported 150 DME from Whitehorse inbound for a landing. ANT 506 was on a track of DUXAR direct to the Whitehorse VOR. On a crossing track to this aircraft was NWA 902 at FL 290 on NCA Track 11. The estimate for ANT 506 for the cross was 2326Z and the estimate for NWA 902 for the cross was 2318Z. The controller who issued the descent clearance was the Low Level controller and he did not know about the traffic at FL 290. The Low Level controller assumed he had contol of ANT 506 when in reality he did not. Since at least 10 minutes on the cross is required to allow the aircraft to be at the same altitude (or cross through each other) and only 8 existed on estimates, a loss of separation would occur. As circumstances worked out, the descending aircraft did not descend until 85 DME from Whitehorse, which put it clear of the NWA 902 flight. Planning and execution did not guarantee this so an Operating Irregularity took place.


CADORS Number 2003C0359
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2003-03-20 - 23:30
Day or Night? Day-time
Fatalities 0
Injuries 0
Aerodrome ID CYXY
Geographic Location Yukon, Canada, North America, Prairie and Northern Region, Whitehorse Intl
TSB Occurrence Number
TSB Class of Investigation
AOR Number 28233
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions,ATM/CNS
Events Conflict - potential,ATS operating irregularity

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