The Transportation Safety Board will release more information this afternoon on its investigation into last week’s crash of a West Wind Aviation turboprop plane at the Fond du Lac airport. Twenty-five people on board, including a baby, were injured when the plane went down seconds after takeoff. No one was killed, although at least four people were seriously injured. None of the injuries is life-threatening.

This type of investigation takes months. It looks at everything from weather conditions to the mechanical integrity of the plane to pilot error. Here is what is known at this point.

The plane took off at 6:15 p.m. on Wednesday, December 13 bound for Stony Rapids. According to passenger Willie John Laurent, a band councillor with the Fond du Lac Denesuline First Nation, the plane was moving up and down and side to side seconds after take off. He then heard scraping and grinding noises as the aircraft began to hit trees before crashing into the ground.

The crash site was less than a kilometre from the runway. Based on the plane’s takeoff speed of 200 km/h and the distance travelled, the plane would have been airborne for only about 20 seconds before it started hitting treetops.

The TSB says the turboprop carved an 800-foot wreckage path as it came down. It came to rest upright but tilted steeply to its right side with the left side of the plane crushed, trapping a number of passengers. The fuselage ruptured around the third row of seats. At least one of the survivors, a teenage boy, was thrown from the plane during impact. He and his cousin, who climbed out of the wreckage, ran for help.

The aircraft was leaking aviation fuel. It was coming down like rain, according to rescuer Raymond Sanger. He rushed to the scene when he heard about the crash and helped free passengers. He says it was not easy to get inside.

“We were ripping the plane apart with our hands and anything we could find,” he said. “At that moment, we were doing everything we could to release those people.”

Laurent said it took about a half an hour to get the emergency door opened on the plane, and it took nearly four hours to get all the passengers off. Most were treated at the medical centres in La Ronge and Stony Rapids, although five were immediately airlifted to hospital in Saskatoon. West Wind Aviation has grounded its five ATR-42’s until it is determined there was no mechanical issue with the plane.

The two flight recorders have been recovered and are being analyzed. Investigators are also looking at weather conditions. According to AccuWeather, it was cloudy with a temperature of minus 9 degrees Celsius and there was no precipitation at the time of the accident. Other factors that will be examined include the takeoff weight of the plane. The maximum takeoff weight is 36,817 pounds. Investigators will also study the instrumentation and settings to determine if the plane was properly configured for takeoff, which could include things like flap settings for the wings. Maintenance records of the plane will also be examined. The aircraft has been in service for 26 years. It was acquired by West Wind Aviation in 2012.

As the investigation continues, Health Canada is doing what it can to help meet the needs of Fond du Lac residents traumatized by the accident. Five mental health therapists have been dispatched to the community.

We will know a little more about the crash at 2:00 Wednesday afternoon when the TSB holds a media briefing in Winnipeg.

It is not uncommon for investigations of this nature to take up to a year to complete, although preliminary findings are relayed to the public if major safety concerns are uncovered.

West Wind Aviation will not be able to put its remaining fleet of ATR-42’s into service until it gets the go-ahead from the TSB.

(PHOTO: A photo of the crashed plane near the Fond du Lac Airport.  Photo by the Transportation Safety Board.)