Incident Attributed To Delayed Use Of Deceleration Devices Following A Long Landing In Heavy Rain

In its investigation report (A15Q0075) released this week, the Transportation Safety Board of Canada cited high speed, a tailwind, a long landing and delayed use of deceleration devices while landing in heavy rain showers, as contributing factors in the 2015 runway overrun of a Westjet Boeing 737 in Montréal, Quebec.

On 5 June 2015, a WestJet Boeing 737 was operating on a scheduled flight from Toronto/Lester B. Pearson International Airport (CYYZ), to Montreal/Pierre Elliott Trudeau International Airport (CYUL). While approaching CYUL, the flight crew observed heavy rain on the weather radar. Once the aircraft was established on final approach, it was cleared to land on Runway 24L. The aircraft touched down beyond the normal touchdown zone and came to rest on the grass past the end of the runway. There were no injuries and no damage to the aircraft.

The investigation determined that the target approach speed was inaccurately calculated, and the aircraft crossed the runway threshold at a speed that was faster than recommended. This, combined with a tailwind and a slightly high flare, resulted in the aircraft touching down beyond the normal touchdown zone, thus reducing the amount of runway available for the aircraft to come to a stop. Additionally, following touchdown, the delayed and non-maximal use of deceleration devices, combined with viscous hydroplaning while landing in heavy rain showers, increased the distance required for the aircraft to come to a stop. An instruction from the control tower to exit at the end of the runway contributed to the minimal use of deceleration devices early in the landing roll, as the crew were attempting to expedite their exit at the end of Runway 24L.

When a runway overrun occurs, it is important that an aircraft have an adequate safety area beyond the end of the runway to reduce adverse consequences. In this occurrence, Runway 24L had a runway end safety area that allowed the aircraft to decelerate in a controlled manner; no one was injured and the aircraft was not damaged. However, there is currently no requirement in Canada for runways to meet international standards and recommended practices for runway end safety areas (TSB recommendation A07-06). Runway overruns continue to occur at Canadian airports and are identified as a key safety issue on the 2016 TSB Watchlist.

WestJet debriefed all training pilots on the occurrence, and the flight safety annual ground school program now covers a number of topics such as overrun characteristics, as well as an incident review of this occurrence.

(Source: Transportation Safety Board of Canada news release. Images from investigation report)

FMI: Investigation Report