Incident
at 70 miles west of Toronto
(Conflict - potential, Conflict - loss of separation, ATS operating irregularity)
The Northwest Airlines, Inc. Airbus A-330 aircraft (operating as NWA49) was on a scheduled IFR flight from Paris (Charles de Gaulle) International Airport, France (LFPG) to Detroit (Metropolitan) International Airport, MI (U.S.A.) (KDTW). The Air Canada Airbus A-320 aircraft (operating as ACA147) was on a scheduled IFR flight from Toronto (LBPIA) (CYYZ) to Vancouver International Airport (CYVR). The flight crew of NWA49 requested descent for Detroit and were issued FL280 (normal descent is to FL300 initially). ACA147 was climbing westbound from Toronto and was cleared to FL290. The Controller passed traffic infomration to the flight crew of ACA147 as an 'Airbus 330 passing right to left 1,000 feet above your altitude' but the A-330 actual descended right to left in front of Air Canada to FL280. Spacing decreased to two (2) miles in airspace where five (5) miles lateral separation is required and altitude separation (of 1,000 feet vertical separation) was not maintained. The flight crew of ACA147 did not get any TCAS indications and NWA49 did not appear to deviate from their course.
Supplemental information from T.S.B. Initial Notification (#A05O0197): The Northwest Airlines Airbus A-330 aircraft (operating as NWA49) was on a scheduled IFR flight from Paris (Charles de Gaulle) International Airport, to Detroit (Metropolitan) International Airport. The Air Canada Airbus A-320 aircraft (operating as ACA147) was on a scheduled IFR flight from Toronto to Vancouver. The flight crew of NWA49 requested descent for Detroit and were issued FL280 (normal descent is to FL300 initially). ACA147 was climbing westbound from Toronto and was cleared to FL290. The Controller passed traffic information to the flight crew of ACA147 stating that the Airbus 330 was passing right to left 1,000 feet above, but the A-330 actually descended to FL280 right to left in front of Air Canada. Spacing decreased to two (2) miles in airspace where five (5) miles lateral separation is required and altitude separation (of 1,000 feet vertical separation) was not maintained.