Incident at EDMONTON INTL AB (CYEG) (TCAS alert, Conflict - potential, ATS operating irregularity)

Summary

2003-03-07: At 2004Z, JZA 8301, a DHC-8 inbound to Edmonton from Grande Prairie was cleared to descend and maintain 9,000 feet. At 2008Z, WJA 14, a B737, departed YEG enroute Vancouver and the crew was cleared to climb to 9,000 feet. At 2008Z, WJA 14 was instructed to level off at 9,000 feet and given traffic 1,000 feet above. At 2009Z, the crew of JZA 8301 was given traffic 1,000 feet below. At 2010Z, JZA 8301 advised they received a TCAS alert as they had been cleared to 9,000 feet, but had leveled off at 10,000 feet due traffic. The two aircraft passed with 1,000 feet separation. Separation required is 1,000 feet vertical however separation was not assured as the Arrival Controller inadvertently cleared JZA 8301 to 9,000 feet instead of 10,000 feet as intended.
2003-03-10: UPDATE ANS and Airspace reported that Nav Canada will hold an Operational Safety Investigation concerning this occurrence. TSB reported that the Jazz Dash 8 was cleared on descent to maintain 9,000 feet ASL on approach to Edmonton from Grande Prairie. A Westjet 727-200 departed Edmonton on route to Vanvouver and was also cleared to 9,000 feet ASL. They were then instructed to level off at 9,000 feet and given a traffic advisory 1,000 feet above them. One minute later, the crew of the arriving Dash 8 advised they had received a TCAS alert as they were getting the clearance, and had levelled off at 10,000 feet due to the traffic below. The aircraft passed with 1,000 feet of separation, and this is what is required. Separation was not assured as the Arrival Controller cleared the Jazz aircraft to 9,000 instead of 10,000 feet as intended.

Details


CADORS Number 2003C0304
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2003-03-06 - 20:10
Day or Night? Day-time
Fatalities 0
Injuries
Aerodrome ID CYEG
Aerodrome Name EDMONTON INTL AB (CYEG)
Geographic Location Alberta, Canada, North America, Prairie and Northern Region, Vicinity of Edmonton
TSB Occurrence Number A03W0046
TSB Class of Investigation Class 5
AOR Number 27994
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions,ATM/CNS
Events TCAS alert,Conflict - potential,ATS operating irregularity


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