September 6, 1996

Incident at PRINCE ALBERT (GLASS FIELD) SK (CYPA) (ATS operating irregularity)

A Northern Dene PA-31 was enroute Prince Albert from Fond-du-Lac Saskatchewan at 7000 feet. DND KUGR16, a F18 was enroute Prince Albert from Cold Lake with an approach and subsequent return to Cold Lake at flight level 280. The pilot of KUGR16 had been given a restriction to cross 20 miles west of Prince Albert at 6000 feet or below after his missed approach. The pilot of C-GGIQ, requested descent and was cleared to 5000 feet. The aircraft was also given an enroute hold geographically clear of the F18. ATC then advised PA FSS to amend the F18's crossing restriction to 20 miles west of PA at 4000 or below. The Air Radio operator determined that KUGR 16's position to be 5 miles west of PA to be descending through 3400 feet. The Air Radio operator misunderstood the intent of the amended instructions, believed them to be applicable to KUGR16's inbound leg and therefore no longer required. This caused C-GGIQ and KUGR16 to have less than the planned separation.