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Air transportation safety investigation A18Q0069

The TSB has completed this investigation. The report was published on 10 July 2019.

Table of contents

Loss of separation

NAV CANADA – Montréal Area Control Centre
Montréal/Pierre Elliott Trudeau International Airport, Quebec, 18 nm NE

View final report

The occurrence

On , an Air Transat Airbus A310-304 aircraft (registration C-GFAT, serial number 545), operating as flight 485 (TSC485), was conducting an instrument flight rules flight from Toronto/Lester B. Pearson International Airport, Ontario, to Montréal/Pierre Elliott Trudeau International Airport, Quebec. At about the same time, a privately owned Cessna 421-B aircraft (registration C-GADG, serial number 421B0802) conducting an instrument flight rules flight, was returning to Montréal/Pierre Elliott Trudeau International Airport from Trois-Rivières Airport, Quebec. The Airbus was inbound from the west, and its flight path would take it north of the airport to commence an approach to land on Runway 24R. The Cessna was inbound from the northeast to commence an approach to land on Runway 24L. At 1901:17 Eastern Daylight Time, when the aircraft were approximately 18 nautical miles northeast of Montréal/Pierre Elliott Trudeau International Airport, a loss of separation occurred. Neither the required vertical separation minimum of 1000 feet nor the lateral separation minimum of 3 nautical miles was maintained. When the loss of separation occurred, they were 200 feet and 2.8 nautical miles from each other. At the closest point, the 2 aircraft came within 500 feet vertically and 1.7 nautical miles laterally of each other. At 1902:22, following instructions from the controllers, the required separation was re-established, and the 2 aircraft landed without incident.

Media materials

News release


Short staffing, deviation from standard procedures led to May 2018 loss of separation near Montreal/Pierre Elliott Trudeau International Airport
Read the news release

Investigation information

Map showing the location of the occurrence


Photo of Kevin Roach

Formerly a senior officer in the Canadian Forces, Mr. Roach has 34 years of military aviation experience as an air traffic controller. He controlled air traffic in several locations, in both visual and instrument flight rules environments, eventually becoming a unit manager.

Mr. Roach joined the Canadian Forces School of Aerospace Control Operations as an air traffic control instructor in 1997, ending his tenure there as chief instructor, responsible for the delivery of air traffic control training for the Royal Canadian Air Force.

Before joining the Transportation Safety Board of Canada in 2013, Mr. Roach was at the Air Traffic Management Coordination Office in Ottawa, where he was responsible for the day-to-day liaison between the Department of National Defence, the Royal Canadian Air Force, Transport Canada and NAV CANADA.

  Download high-resolution photos from the TSB Flickr page.

Class of investigation

This is a class 3 investigation. These investigations analyze a small number of safety issues, and may result in recommendations. Class 3 investigations are generally completed within 450 days. For more information, see the Policy on Occurrence Classification.

TSB investigation process

There are 3 phases to a TSB investigation

  1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
  2. Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
  3. Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.

For more information, see our Investigation process page.

The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.