From DaveReidUK's post 181..
"The Canadian TSB, on the other hand, opened an investigation on 17th March, categorising the event as a Class 3 - defined as:
"Individual occurrences that do not meet the criteria of Class 2 occurrences may be investigated when
1. there is significant public expectation that the TSB should independently make findings as to cause(s) and contributing factors; or
2. there is potential for better understanding the latent unsafe conditions contributing to a significant safety issue; or
3, a government representative so requests (pursuant to Section 14(2) of the CTAISB Act); or the Board must do so to meet its obligations or commitments."
As of today I don't know what the status of the TSB's investigation is on this event.