I have no idea whether the correct default position should be to ground or not to ground these planes. But it's clear that the investigation is in-progress and

I have no idea whether the correct default position should be to ground or not to ground these planes. But it's clear that the investigation is in-progress and their statement was not "we don't believe it" but "Thus far, our review ... provides no basis to order grounding the aircraft ... Nor have other civil aviation authorities provided data to us that would warrant action." > Even if they are right, the right thing to do is thoroughly review past incidents and issue a finding. Isn't that precisely what they're doing now? Also from the FAA's statement: "... if any issues affecting the continued airworthiness of the aircraft are identified, the FAA will take immediate and appropriate action."