I disagree. The last sentence kinda strongly implies that there was no redundancy:

"the existing brakes does not constitute a redundant system"

Or from the Portuguese report:

  Desta forma, não constitui um sistema redundante à falha dessa ligação

  Therefore, it does not constitute a redundant system in the event of this connection failing.

It turns out that the brakes were critical and they didn't work for whatever reason (design or maintenance or operation or unforseen failure)