But the only aircraft Boeing are likely to sell in any numbers are twins. The FAA have a dual mandate, not just to regulate aviation in the USA but also to promote American commercial interests. This ruling seems to demonstrate the latter quite adequately. I doubt the NTSB had anything to do with this ruling, nor do the FAA always pay heed to their findings, especially if those findings involve people having to spend money. Fortunately there are other regulatory bodies in the world and I doubt the FAA will find such ready approval for 330 minutes ETOPS or onerous restrictions on 3 or 4 engined aircraft from them.