Friday, July 23, 2021

Runway conditions and limited visual cues attributed to cause of Terrace aircraft incident of January 2020

The WestJet Encore plane that was the subject of
a Transportation Safety Board of Canada investigation into
a challenging landing in Terrace in January of 2020

(photo from TSB of Canada website)

The Transportation Safety Board of Canada has released its report into an incident at the Terrace airport in January of 2020, providing the details into its findings into the 'runway excursion' that took place for a West Jet Encore flight on January 31st.

The incident which closed the Terrace airport for a number of days, did not have any reports of injuries during the course of the landing.

In its investigation report (A20P0013) released Thursday, the Transportation Safety Board of Canada (TSB) found that limited visual cues due to falling snow and a snow-covered runway contributed to the 2020 runway excursion involving a WestJet Encore De Havilland of Canada Ltd. DHC-8-402 in Terrace, British Columbia.

From the report, the TSB of Canada notes of the situation that evolved as the WestJet flight consisting of four crew members and 43 passengers arrived in Terrace.

During the landing roll, the aircraft drifted left from the snow-cleared area of the runway and the left main landing gear exited the runway surface, travelling for approximately 400 feet before returning to the runway. During the runway excursion, the aircraft’s nose landing gear collapsed. The aircraft came to a stop in the centre of the runway. The passengers were transported to the airport terminal by bus approximately 30 minutes after landing. No injuries were reported. The damage to the aircraft included the collapsed nose landing gear and damaged right propeller blades. 

The investigation found that, given the falling snow and the snow-covered runway, there were limited visual cues available to the flight crew, which decreased their ability to accurately judge the aircraft’s lateral position once it was beyond the runway threshold. Snow clearing operations cleared the centre 100 feet of the runway, which resulted in windrows that were approximately 18 inches high along the edges of the cleared area. This reduced the pilot’s lateral maneuvering room during the landing.

A windrow along the Terrace airport runway, part of the
investigation into the January 2020 landing

(from the TSB of Canada website)

Other conditions that were part of the incident was a landing 10 feet left of the centre line owing to control
inputs and wind conditions, along with a strong gust which  put the plane into an windrow, which 
contributed to a further deviation from the normal route of travel on the runway.

From that, the report notes:

As a result, the aircraft was pulled to the left and travelled through the uncleared portion of the runway. During the runway excursion, snow and ice became packed in the nose landing gear bay and caused structural deformation. Consequently, the nose landing gear was no longer being held in place and collapsed rearward into the fuselage, causing substantial damage to the aircraft. 

Finally, the investigation also determined that, if aircraft operators do not provide pilots with all the possible tools and relevant information to assess runway suitability for landing, pilots may not evaluate all potential threats and may make decisions based on incomplete or conflicting information.

The Safety actions taken as a result of the incident can be reviewed below:

The Transportation Safety Board of Canada Investigation page is available here.

In the days following the incident, the Terrace airport operations were suspended until the plane could be removed from its placement. Regional media coverage of the incident at the time can be reviewed here.

For the latest notes on aviation across the Northwest see our archive page here

No comments:

Post a Comment