Prior to 1990,
Transport Canada's
Aircraft Accident Investigation Branch (, 1960–1984) and its successor the
Canadian Aviation Safety Board () or CASB (1984–1990) were responsible for investigation of air incidents. Before 1990, investigations and actions were taken by Transport Canada and even after 1984 the findings from CASB were not binding for Transport Canada to respond to. It was formed in response to a number of high-profile accidents, following which the Government of Canada identified the need for an independent, multi-modal investigation agency. The headquarters are located in Place du Centre in Gatineau, Quebec. The provisions of the
Canadian Transportation Accident Investigation and Safety Board Act were written to establish an independent relationship between the agency and the Government of Canada. This agency's first major test came with the crash of
Swissair Flight 111 on September 2, 1998, the largest single aviation accident on Canadian territory since the 1985 crash of
Arrow Air Flight 1285R. The TSB delivered its report on the accident on March 27, 2003, some 4½ years after the accident and at a cost of $57 million, making it the most complex and costly accident investigation in Canadian history to that date. From 2005 to 2010, the TSB concluded a number of investigations into high-profile accidents, including: • the crash of
Air France Flight 358; • the
Cheakamus River derailment; • the sinking of
Queen of the North; • the loss overboard of a crewmember of
Picton Castle; • the
Burnaby pipeline rupture; • the crash of
Cougar Helicopters Flight 91; • the sinking of
Concordia. To increase the uptake of its recommendations and address accident patterns, the TSB launched its Watchlist in 2010, which points to nine critical safety issues troubling Canada's transportation system. On 3 December 2013, in the wake of the
Lac-Mégantic rail disaster the previous July, it was reported that the number of runaway trains was triple the number documented by the TSB. In August 2014, the TSB released the report on its investigation into the July 2013 Lac-Mégantic derailment. In a news conference, then TSB chair Wendy Tadros described how eighteen factors played a role in the disaster including a "weak safety culture" at the now-defunct Montreal, Maine & Atlantic Railways with "a lack of standards, poor training and easily punctured tanks." The TSB also blamed
Transport Canada, the regulator, for not doing thorough safety audits often enough on railways "to know how those companies were really managing, or not managing, risk." the organization issued two safety advisories on April 11, 2019 to Transport Canada . The first called attention to the need for effective safety procedures to be applied to all trains stopped in emergency on both "heavy grades" and "mountain grades" and the second highlighted the need to review the efficacy of the inspection and maintenance procedures for grain hopper cars used in CP's unit grain train operations (and for other railways as applicable), and ensure that these cars can be operated safely at all times. In January 2020, the Senior Investigator was reassigned in order to protect the integrity and objectivity of the investigation after voicing an opinion implying civil or criminal liability. The TSB labelled the comments made to
The Fifth Estate journalists as "completely inappropriate" as the mandate of the TSB is to make findings as to causes and contributing factors of a transportation occurrence, but not to assign fault or determine civil or criminal liability. The CBC documentary pointed out what seemed to be a problem, where the private police service of CP Rail investigated the accident. A
CPPS officer was also resigned over these circumstances. As of June 2020, the investigation is ongoing. ==Mandate and direction==