"Is this also factual rumour or is there hard evidence of this?"
I would suggest you read the Hansard from the senate inquiry into the First ATSB report, also many of the submissions to that report that completely debunked much of the ATSB's assumptions.
But this thread is not so much about the Norfolk incident as the unconscionable amount of time the ATSB takes to complete a report. That I believe is in itself an impediment to safety as illustrated by Mr. Smith. A timely report into an incident could have prevented an accident in which people lost their lives.