I hope the FAA is conducting a formal investigation as they did with the BA747 3-engine incident.
and how would you suggest that they perform the investigation?
Should they take statements from other pilots like we do on this board?
I've been through these kind of investigations and the bottom line I got told one day was
"the Captain is the Captain"
What you start with is a review of the carrier's procedures and the lee way allowed the captain. It's pretty difficult for the FAA to do anything after the fact, other than review procedures.