With great respect for all who post here, allow me to briefly summarize an area that has gotten little credence, perhaps understandably so.
The Industry, like others, is not without elements of other highly competitive and cutthroat endeavours at times. Betrayal is a part of modern commerce as it was in the days of the Silk Road and the Rum, molasses, and slave triangle.
Financial? Tech? Airframe? Regulatory Agencies, and investigative Boards?
Farming out highly critical aspects of a large and highly visible Investigation is par for the course, but comes with the possibility of failure (s), and inaccuracies. As the "Slick" was dismissed out of hand by BEA without evidence, followed by garbled and nonsensical language("Whether voluntary or not,") The fumbling of the Medical data, conclusions about structural evidence without "substantiating data", and the limitless hypothesizing about a flight path that is without evidence of any kind, What should have been a straightforward discussion of "Smoke on the Water" was ignored, actively, might I say, by the Trustees of Aviation safety, while 20 million was spent trying not to find the aircraft.
oily film? bunker fuel dumped by an anonymous ship,
Fuel? voluntary or not, which makes no Flight sense.
En Ligne de Vol? Useless phrase, impossible to know, and misleading, of course.