What happened
On a scheduled flight from New York City to Casablanca, a Boeing 747-200 operated by Royal Air Maroc arrived at Dorval / Montréal International Airport for a scheduled stop. The flight crew was operating on runway 24R, which had a reduced landing distance available of 8,000 feet due to ongoing construction.
During the approach, the crew maintained a speed higher than the reference speed to account for potential wind shear from a nearby storm cell. As the aircraft crossed the threshold, a sudden shift in wind resulted in a 15-knot tailwind component. The aircraft made a firm touchdown approximately 1,700 feet from the threshold.
Despite the use of thrust reversers and heavy braking, the aircraft could not stop within the available distance. The plane traveled 700 feet beyond the relocated runway end and struck barriers. During the overrun, tower personnel observed flames exiting the No. 2 engine. The engine subsequently overheated and shut down. There were no injuries and no evacuation was required, though the No. 2 engine sustained internal damage.
The investigation
The TSB examined flight data recorder and cockpit voice recorder data, as well as the aircraft's mechanical condition. The investigation focused on the landing performance, the impact of the wind conditions, and the runway surface characteristics. Investigators analyzed the crew's use of braking systems and landing techniques, specifically the decision to use the minimum automatic braking setting. The investigation also looked into the availability of runway friction information and the adequacy of NOTAMs issued by the airport authority.
Findings
Several factors contributed to the runway excursion:
- The pilot flying used a landing technique that reduced excess speed during the flare, which increased the required landing distance.
- The 15-knot tailwind component significantly extended the landing roll.
- The automatic braking system was set to minimum instead of the recommended medium setting.
- The runway surface, characterized by wet conditions and rubber accumulation, was prone to viscous hydroplaning.
- The flight crew did not consult landing performance diagrams, which would have indicated that the available distance was insufficient for the given conditions.
- The crew lacked critical information regarding the slippery nature of the runway, as the airport authority had not issued a NOTAM despite recommendations to do so.