Pilot error and possibly a language barrier in South Shore plane crash

Canada's Transportation Safety Board is blaming pilot error for the collision of two small planes over Promenades Saint Bruno on the South Shore last year.  

The investigation showed both pilots strayed from their assigned altitude on March 17, 2017.  One was 100 feet too low and the other was 400 feet too high.  

One was a licensed pilot undergoing commercial training.  He survived the crash with serious injuries.

The other was a student pilot, and he died.  

The Board determined that the Cessna at the lower altitude hit the other plane from below, neither pilot able to see the other craft.  

The board is questioning whether language proficiency had been properly checked.  Both flyers were from overseas and had neither French nor English as a first language, but had passed an English proficiency test.  The Board says Transport Canada's oversight of language proficiency testing is largely bureaucratic, with no indicators as to reliability or validity.

Air traffic controllers had radioed altitude warnings several times prior to the crash.