The Transportation Safety Board of Canada (TSB) released a report Tuesday on the March 7, 2020 incident, which it described as a “runway intrusion and collision hazard” in Toronto Pearson.
According to the TSB report, an Air Canada Embraer 190 was taking off from Runway 06L shortly before 9:50 a.m.  The plane, bound for Denver, carried 83 passengers and four crew members.
As the plane took off, an Air Canada Boeing 777 was ordered to line up on the same runway.  The plane, which was going to Halifax, had 345 passengers and 14 crew members on board.
“As the Embraer 190 accelerated during takeoff, it hit a bird,” TSB said.  “The flight crew started a rejected take-off and made a radio call to indicate that they were rejecting the take-off.”
TSB said the Boeing 777 flight crew and air traffic control missed the take-off call rejected by the Embraer 190 because at the same time the Boeing 777 pilot was reading back his own take-off license at the same frequency.
“The inspector issued a take-off license for the Boeing 777, ignoring the bird’s blow, and the Embraer 190 rejected the take-off,” the report said.
The Boeing 777 began to accelerate.
“For the next 25 seconds, the inspector turned his attention to the north end of the airport, where two aircraft were approaching runway 05… from his screens, he could see the Boeing 777 and the Embraer 190, but saw no collision that season, “the report said.
According to the report, the flight crew of the Boeing 777 reached a maximum speed of 231 km / h before realizing the other plane in front of it and rejected the take-off.
At that point, the separation between the two aircraft narrowed to the nearest 1,646 meters, TSB reported.
“The inspector confirmed the rejected take-off with the flight crew, still ignoring the presence of the Embraer 190 on the runway and waiting to provide further assistance to the Boeing 777,” the report said.  “After searching for the expected position of the Embraer 190 (in the air, at the runway departure end), the inspector saw the Embraer 190 in the runway and realized that he had also rejected the take-off.”
There were no injuries or damage to any of the aircraft during the incident, TSB reported.
“The investigation found that the Embraer 190 transponder transmitted that the aircraft was in the air as the aircraft accelerated more than 50 knots,” the report said.  “As a result, although it complied with current standards, an inaccurate condition was transmitted to the air while the aircraft remained on the ground during take-off and declined to take off.”
“The use of this data by the NAV CANADA (RIMCAS) intrusion and runway collision monitoring subsystem led to inaccurate identification of the Embraer 190 and Boeing 777 in the air while these two aircraft were still on the ground. This resulted in delays. and inaccurate RIMCAS warnings and delayed the air traffic controller’s response to the risk of collision. “
TSB said the risk was mitigated when the Boeing 777 flight crew refused to take off.