Aviation Safety Issues Investigation A17O0038

Runway incursions between the parallel runways on the south complex of
Toronto/Lester B. Pearson International Airport

In May 2017, the Transportation Safety Board of Canada (TSB) launched a safety issues investigation (SII) that will examine in depth multiple runway incursions that have occurred between runways 06L/24R and 06R/24L at Toronto/Lester B. Pearson International Airport (CYYZ) from June 2012 to June 2017.

An SII (also known as a Class 4 investigation) is broad in scope and examines multiple occurrences in order to identify underlying safety issues. The Board may make recommendations to address any systemic deficiencies it identifies. It will communicate its findings to the public once the investigation is complete.

Terms of reference


In June 2012, the Greater Toronto Airport Authority (GTAA) completed an investigation into runway incursions on the south complex of CYYZ. It identified 40 occurrences of interest between 2004 and the end of 2011, of which 20 were inner runway incursions (incursions between the two parallel runways). The GTAA implemented a runway incursion plan based on its findings, and completed the changes outlined in the plan at the end of 2013.

From the last incursion recorded in the GTAA investigation in December 2011 to May 2017 there have been another 22 inner runway incursions at the CYYZ south complex: 13 prior to the completion of the GTAA's runway incursion plan in 2013, and 9 since then.

The south complex has characteristics not found at other airports in Canada and elsewhere in the world.


The SII will examine the factors contributing to the incidence of inner runway incursions on the CYYZ south complex, the adequacy of existing defences against these occurrences, and the potential for additional defences to mitigate residual risks.

The investigation will specifically exclude any incursions that do not occur between the parallel runways on the CYYZ south complex.


The SII will be conducted in three phases.

Phase 1 – Field phase (largely complete)

Available data was collected following each of the 22 incidents that occurred after December 2011. This work included

  • gathering radar, audio, flight data and cockpit voice recordings, where possible;
  • interviewing or obtaining statements from flight crews and air traffic controllers; and
  • collecting background information, documentation, and research.

Phase 2 – Analysis phase (May 2017 to October 2017)

This phase will include

  • a macro-level review of runway incursions on the south complex;
  • an in-depth safety analysis of select occurrences;
  • an analysis of airport and aircraft features that could be contributing to these incursions; and
  • a review of potential additional defences to mitigate the likelihood or severity of runway incursions on the south complex.

Phase 3 – Report writing phase (October  2017 to December 2017)

Once the information has been analyzed and validated, a draft report will be prepared.

The Board will review the initial draft report and may choose to engage outside parties in a designated-reviewers process.

Once the investigation is complete, the Board will report its findings to the public and make recommendations if required.


Photo of Ewan Tasker

Ewan Tasker has over 20 years of civil aviation experience. He joined the TSB in 2008, and is now a regional senior investigator based out of Richmond Hill, Ontario. Since joining the TSB, he has been the investigator-in-charge of more than 250 occurrences, including 11 major investigations.

Before joining the TSB, Mr. Tasker flew commercially throughout North and South America, accrued over 7000 hours of flight time, and obtained airline transport pilot licences from 3 different regulatory bodies. During his "from-the-ground-up" career, he has worked every position, from baggage handler to chief pilot. Mr. Tasker is also a Transport Canada–licensed air traffic controller.