Relative to BEA "independence". All Govt. agencies are interdependent.
What is crucial is NOT independence, but objectivity. Major work is done by AB and others here. Analysis, both engineering and operational, is conducted by interests who have an abiding interest in the outcome of the investigation. This is a given, and not disqualifying; they have the records and the expertise. What is very important is the final product produced by the Agency.
DJ77 re: your last post. Any Pitot system that melted ice at the orifice only to send it to a drain to refreeze would be laughed at, it is as you say.
I don't think the Pitots are framed correctly here, as I have said, to pin all Ua/s on freezing pitots (three at a time), stretches credulity.
Will