On 30 January 2016, the Air Canada Embraer 190-100IGW (registration C-FNAW, serial number 19000149) was operating as flight 726 (ACA726) on a scheduled flight from Toronto/Lester B. Pearson International Airport, Ontario, to LaGuardia Airport, New York, United States. ACA726 taxied over the hold line and onto Runway 24R without authorization at the same time that an Air Canada Airbus 320-214 (registration C-FZQS, serial number 2145) operating as flight 1259 (ACA1259), was on final approach for landing on the same runway. At 2101:38 Eastern Standard Time, as ACA726 was turning onto the runway centreline, the flight crew of ACA1259, which was now 0.41 nautical miles from the Runway 24R threshold and at 270 feet above ground level (AGL), reported to the airport controller that there was an aircraft on the runway and that they were overshooting the runway. ACA1259 was climbing through 580 feet AGL when it flew over ACA726. Air traffic control had not been aware of the runway incursion before being notified by ACA1259 that there was an aircraft on the runway. The incursion occurred during hours of darkness.