Personally, I would prefer to send someone with technical expertise on product or process or both, but only if the supplier has kind of "thrown in the towel" and admitted an inability to resolve the situation on its own. It is one of the reasons I mentioned "attitude" in my previous post.
Third party auditors do not need technical competence in the product or process to determine if there is sufficient process and adherence to the process and thus decide if the process needs tweaking or if the operators need tweaking to follow the process.
Third party auditors do not need technical competence in the product or process to determine if there is sufficient process and adherence to the process and thus decide if the process needs tweaking or if the operators need tweaking to follow the process.
The primary questions which seem to be missing from this thread are whether
- supplier acknowledges the n/c as valid
- supplier agrees the n/c originated in his shop, not in shipping or at customer or at one of his suppliers
- supplier has presented a cogent description of his efforts to date in trying to resolve the situation and has no solution
My guess is that perhaps 80% or more of the situations such as the OP's can be handled from a distance, and only extreme cases call for in-person intervention. As you suggested earlier, those cases should be handled as offering help rather than as blame-seeking missions. If the person sent isn't qualified to troubleshoot the process(es), there's no point in sending him.