I think it's a given that the Afghan "authorities" aren't much of an actual authority beyond the legal definition. The real work and the real input will come from US sources and ISAF resources on scene. The NTSB, Boeing, National, and others will all have input and be a part of the investigation, though none are the official spokesmen for the event.

Had the NTSB been in charge of this event, there is no way such hasty conclusions would have been announced, especially not as they were. The "preliminary" data that was put out by press conference was more of a political dog and pony show, and speculation at best.

I would surmise that others wrapt in the actual investigation were less than happy with the Afghani presentation.