What happened
On the evening of May 11, 2000, an Air Canada Douglas DC-9, registration C-FTLM, was accelerating for takeoff on Runway 2/30 at Edmonton International Airport. The aircraft, carrying 86 passengers and 5 crew members, was operating at a high takeoff weight that required a zero-flap configuration.
Immediately after the rotation call, the aircraft flew through a flock of birds. The crew heard loud thuds and rhythmic thumping, and the right engine's engine-pressure ratio (EPR) and fan speed began to decrease. The captain also observed fluctuations in the left engine's EPR indicator. Believing that both engines had lost significant power, the captain decided to reject the takeoff.
Although the aircraft had already passed its decision speed (V1), the captain took control, closed the throttles, and applied reverse thrust. However, only the left engine operated in reverse. Despite full braking, the aircraft could not stop within the remaining runway length, overrunning onto the grass at approximately 50 knots and coming to a halt 500 feet past the runway centerline lights. There were no injuries to the passengers or crew.
The investigation
The investigation focused on the engine performance, the timing of the rejected takeoff, and the local wildlife environment. Investigators examined the flight data recorder, which showed a sharp drop in the right engine's EPR at 163 knots, followed by a deceleration of the left engine as the throttles were closed.
Maintenance inspections revealed that the right engine had sustained extensive damage from bird ingestion, while the left engine suffered turbine blade damage. The investigation also reviewed the airport's wildlife management practices, noting that recent efforts to burn dry grass to reduce rodent populations had likely attracted birds to the area. While bird activity had been noted on the ATIS, the crew had heard a transmission suggesting the hazard had moved, leading them to believe it was safe to depart.
Findings
- The primary cause of the incident was the ingestion of ring-billed gulls into the engines during the takeoff roll.
- The takeoff was rejected after the aircraft had exceeded V1 speed, a decision driven by the captain's perception that both engines were compromised.
- The aircraft's high takeoff weight and the zero-flap setting left very little margin for error; the delay in initiating the stop, combined with the speed at the time of the reject, made a runway overrun unavoidable.
- Recent wildlife management actions, specifically burning grass to control rodents, had inadvertently increased bird presence near the runways.