peekey:
So when an accident or incident is serious but does not involve fatalities, the NTSB will routinely delegate the field investigation work to the FAA.
True enough with light aircraft accidents. But, not with air carrier operations. The fact it is a foreign carrier has relevance to the FAA but not the NTSB. The location of an air carrier accident establishes NTSB jurisdiction.
I.e., the FAA will collect and take into custody all the evidence including photographs, any wreckage, CVR/FDR data, crew/witness interviews, etc., then forward them to the NTSB for final analysis and determination of Probable Cause.
That's a new one on me. The Board is not inclined to analyze work by FAA investigators unless they were assisting the NTSB investigators in the field. Further, the FAA has neither the facilities nor expertise to assess CVRs and FDR data. Finally, the Board does not issue probable causes when the FAA does an accident investigation.