Without intending to do so, I may have hyperfocused my disagreement with BEA terminology. In and of itself, the phrase en ligne de vol is reasonably benign. To take issue with it involves a very strict 'raison d'etre'. It may be a non charged description of horizontal for whomever wrote the piece. The writer isn't responsible, the group who approved the text is. As Surplus1 so eloquently points out, this report is composed by parties who have well defined and difficult to disguise interests in the ultimate understanding of the piece by all who read it. As such, it is a rehash of all the information already known, exclusion of information that would lay responsibility on an interested party, and is essentially useless.
Without substantiating a conclusion of hull integrity, they claim it by 'visual inspection'. No supporting engineering, no metallurgy, no independent or reviewed analysis. They rely solely on their authority to conclude to do so. This report is opportunistically political.
Your evidence of this appears to be: that you don't speak French very well. What would you have said about a Frenchman who made similar assertions about an FAA/NTSB report entirely because he didn't understand an unusual phrase in English?