March 14, 2003

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

UPDATE TSB reported that CPB 202, a Jetstream 3112, registered C-FMIP, was en route on an IFR flight from Calgary to Edmonton at 16,000 feet. CNK 633, a Learjet 35A, registered C-GTJL, was also en route on an IFR flight from Calgary to Edmonton at FL 260. At 1700 MST, the Red Deer Enroute Sector Controller cleared CPB 202 to 10,000 feet and five minutes later, the same Controller also cleared CNK 633 to 10,000 feet. After both aircraft had contacted the Edmonton Arrival Terminal Controller, a potential conflict was detected, and CNK 633, which was overtaking CPB 202, was instructed to stop the descent at 17,000 feet. Both aircraft arrived at their destination without further incident. There was no loss of separation, however safety was not assured when both aircraft were cleared to the same altitude, with a significant speed differential between them.
UPDATE ANS and Airspace reported that Nav Canada will hold an Operational Safety Investigation concerning this occurrence.
CPB 202, a BAe Jetstream 31, was IFR Calgary (YYC) to City Centre Airport (YXD) at 16,000 feet. CNK 633, a Lear 35, was also enroute IFR YYC to YXD at FL 260. At 0002Z, the Enroute Controller cleared CPB 202 to 10,000 feet ASL with instructions to contact the Terminal Controller on 120.5 Mhz. At 0005Z the Enroute Controller cleared CNK 633 to 10,000 feet ASL with instructions to contact the Terminal Controller on 120.5 Mhz. When contacted by CNK 633, the Terminal Controller cleared CNK 633 to maintain 17,000 feet ASL. Both aircraft arrived at YXD without further incident. No loss of separation occurred, however, safety was not assured when the Enroute Controller cleared CNK 633 (which was overtaking CPB 202) to the same altitude.