The Transportation Safety Board has released an update on its investigation into the December 13, 2017 plane crash at Fond-du-Lac.

The twin-engine aircraft owned by West Wind Aviation went down shortly after taking off with 22 passengers and three crew on board.

Nine people were seriously injured.

Sixteen other people were also injured and one person later died of those injuries.

The TSB has concluded the plane was not overweight.

The aircraft was not de-iced before takeoff, although there was some ice in clouds in the area.

Officials say there are still a number of issues to be investigated including why the aircraft was not de-iced before takeoff, determining the effects of weather and runway surface conditions and an examination of flight controls.

As part of the investigation, the TSB will be conducting a data gathering exercise regarding aircraft operations at remote airports in Canada.

It is not known how long it will take to complete the investigation into the crash.

The update is available at:

(PHOTO: A photo of December’s crash provided by the TSB.)