Incident at Gander Oceanic (Conflict - loss of separation, ATM - NAVAIDS/radar)


2001-07-17: COA35 was radar identified on route Scrod direct VALIE at FL 350. For some reason the radar target disappeared. DAL 67, on the same routing, one minute behind at FL 330 requested FL 350. Not observing any traffic on radar the controller cleared DAL 67 to FL 350. As DAL 67 began to climb, he observed a TCAS RA. TSB Case closed.
2001-07-18: TSB update:COA35, a Boeing 777 aircraft, was on a routing of SCROD direct VALIE at FL350. DAL67, a Boeing 767 aircraft, was on the same routing, one minute behind COA35, at FL330. Both these aircraft were radar identified, however, the radar target for COA35 was alternately disappearing and then reappearing on the controllers radar screen. A review of the radar information revealed that this was occurring during the first 50 to 60 miles after COA35 progressed by SCROD. During this time, DAL67 requested a climb to FL350 and the controller, not observing any traffic on radar, cleared the flight to FL350. AS DAL67 was climbing through FL340 they received a TCAS RA. The crew advised Gander ATC and the controller re-cleared DAL67 to FL340. Nav Canada will be conducting a fact finding board.


CADORS Number 2001A0432
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2001-07-16 - 13:45
Day or Night? Day-time
Fatalities 0
Aerodrome ID
Aerodrome Name
Geographic Location Gander Oceanic, Atlantic Region, Gander Oceanic
TSB Occurrence Number A01A0078
TSB Class of Investigation Class 5
AOR Number 16435
Reported By NAV CANADA
Categories Airprox/TCAS alert/loss of separation/(near) midair collisions,ATM/CNS
Events Conflict - loss of separation,ATM - NAVAIDS/radar

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