Incident at HALIFAX / STANFIELD INTL NS (CYHZ) (Conflict - loss of separation)


2005-05-31: TSB Upadte: A05A0058: The Sobey's Group Inc. Astra SPX, mark C-GBSW, was IFR and had been vectored for the back-course localizer approach to RWY 33. Once the aircraft was on the localizer the aircraft was switched to Halifax tower control. A Canadian Helicopters Sikorski 61, mark C-GIMN, was IFR and on a right hand downwind being vectored for the same approach. The terminal controller observed the Astra SPX making a right turn away from the localizer toward the S61. The terminal controller contacted the tower controller to question what the Astra was doing. At about the same time the tower controller had contacted the Astra crew and informed the terminal controller that the Astra SPX was now turning back to the approach path. During the sequence the terminal controller had issued an immediate left turn to the S61. Separation had deteriorated to 2.8 NM laterally and 100 feet vertically. When tower called the Astra crew they had broken though cloud and could see the runway clearly for a visual approach; an overshoot was not carried out. The company reported that they operate two Astra aircraft which are configured differently with regard to avionics switching and the FMS. At the initial stages of intercepting the ILS for Runway 33 a crewmember had pressed the approach button as opposed to the back course button. This initiated a sharp left turn instead of a slight right turn to track the localizer on the approach. The other company aircraft does not feature a back course button; configuring for a back course in that aircraft is done by manipulating a different series of buttons. The company will highlight this issue during their next safety meeting
2005-05-20: CGBSW was vectored and cleared for a back course localizer for runway 33 at Halifax and was changed to tower frequency when observed on the localizer. CGIMN was on a right hand downwind being vectored for the same approach. Terminal controller observed CGBSW making a right turn off the localizer toward CGIMN. He immediately asked tower what the aircraft was doing and was advised that CGBSE was now turning back towards the airport. The terminal controller issued CGIMN an immediate left turn to a heading of 150 degrees. Separation deteriorated to 2.8 NM and 100ft vertical.


CADORS Number 2005A0321
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2005-05-19 - 23:05
Day or Night?
Fatalities 0
Injuries 0
Aerodrome ID CYHZ
Geographic Location Nova Scotia, Canada, North America, Atlantic Region,
TSB Occurrence Number
TSB Class of Investigation
AOR Number 56131V1
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions
Events Conflict - loss of separation

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