Incident at THUNDER BAY ON (CYQT) (Conflict - loss of separation, ATS operating irregularity)

1997-03-20: An operating irregularity occurred when one of two opposing aircraft was cleared to climb to a higher altitude. Canadian Flight 16, a DC-10, was maintaining FL 370, enroute between Calgary and Toronto on Airway Empress T469 Dryden. Air Canada Flight 127, an A320, was at FL 350, enroute from Toronto to Edmonton, via Sault Ste. Marie. When the aircraft were head-on and 80 to 90 miles apart, Air Canada Flight 127 requested permission to climb to FL 390, estimating the climb would take 8 minutes. The Controller calculated that the aircraft would pass in 13 minutes, and sufficient vertical separation would be assured. Air Canada 127 was granted permission to climb to FL 390. The aircraft was observed to climb slower than anticipated. The Air Canada flight was asked to expedite the climb, but the aircraft did not attain FL 390 quickly enough for the required separation. The two aircraft passed each other with less than two miles lateral and 1,700 feet vertical separation. A 5-mile lateral or 2,000 foot vertical separation is required. By the time it was apparent that the vertical separation would not be maintained, insufficient time remained to vector the aircraft to attain lateral separation. Traffic was light to moderate in the control zone, and the positions were fully staffed at the time of the occurrence. The ATC Shift Manager is investigating the operating irregularity.