A Mayday call is a broadcast
Don't agree. It is a radio transmission but it is not a "broadcast" in the sense of BBC Radio but, officially at least, limited only to people who need to know. It is effectively a private communication that should be shared perhaps with the police, the AAIB and other interested parties. But there is no public interest in telling it to the tabloids. It does not add to our understanding of the causes of the accident. It would be enough to say that the mayday call was cut off.