The Transportation Safety Board of Canada is reviewing two incidents that occurred in recent days at Toronto Pearson International airport.
The agency has sent staff to Toronto to investigate a runway incursion on 8 August involving an Embraer 175 from Chicago.
After landing on Toronto's Runway 24L at 17:31 local time, controllers instructed the pilots of the E175 to hold short before crossing Runway 24R.
The aircraft, however, crossed the hold short line, prompting the investigation, the agency says.
The TSB does not say whether the E175 came close to any aircraft on runway 24R, and it does not name the airline that operated the E175.
"We are collecting information at this point, and conducting interviews," the TSB tells FlightGlobal.
However, the only E175 arriving at Toronto from Chicago around that time on 8 August was an Envoy Air aircraft operating flight 3765 for American Airlines, according to multiple online flight tracking sites.
American did not immediately respond to a request for comment.
The TSB is also gathering information about a ground collision on 5 August between two aircraft at Toronto Pearson, the agency says.
According to Air Canada, one of its Boeing 767-300s clipped wings with an aircraft operated by Polish carrier LOT at about 22:30 local time that day.
The Air Canada aircraft had operated flight 1713 from Punta Canada and was approaching the gate at Toronto when the incident occurred, the carrier says.
None of the 286 passengers on the Air Canada aircraft were injured, Air Canada adds.
The LOT aircraft was a 787, according to photographs posted on social media. LOT did not respond to a request for comment.