It's Air Canada's fault! As such they should be the only ones getting sued but we know in the real world everyone is going to get sued that is involved in some way with this accident.
1- This accident could have been easily avoided if Air Canada had installed the proper equipment in their aircrafts (older 320s).
2- The pilots screwed up (for whatever reasons) causing an accident, end of story. Again since they are Air Canada employees, it's Air Canada's problem.