Not conclusive
"He said the explosion would not be secondary to engine failure, which would remove the assumption of the accident."
This does not remove the possibility of an accident. For example, a fuel tank explosion like TWA800 need not be related to an engine failure.
It sounds like a probable fact that the explosion was not preceded by abnormal readings, but that fact is leading to an inappropriate inference of a non-accidental cause.
BTW... I used Google Chrome to translate the web page from French to English, so the above quote is a result of an automatic translation. Chrome is very handy for this purpose - in my case, it put up a question above the page asking if I wanted it translated.