The CAA in this case I expect will await the outcome of whatever investigation(s) the NTSB or FAA make. If the FAA considder this a reportable incident then the normal procedures will apply and the NTSB or FAA may make certain recomendations to operators and to regulatory authorities. Until then, the CAA can simply wait and see.
As for the case under review - This aircraft suffered and engine failure shortly after departure. It then spent several hours crossing a continent and on reaching the eastern shore of that continent one can safely say that the relative reliability of the remaining engines had been proven. At all times over that continent, the aircraft was within easy reach of many alternate airfields should one have been required. Having consulted with operations and the maintenance organisation, the decision was made to cross the Atlantic in an aircraft with 3 serviceable engines and suficient performance. While over the ocean the aircraft was closer in flying time with a further engine failure to the ETOPS alternates than other twin engine aircraft making the same crossing at the same time.
The pilot later declared an emergency and diverted because of uncertainty regarding the actual amount of fuel remaining. The aircraft had the required minimum fuel when it landed. The reasoning behing declaring an emergency is that in the UK, fuel emergency or fuel priority calls are not recognised and the only method of avoiding possible delay in such cases is to declare an emergency. The US however permits pilots to call for a fuel priority thus avoiding having to declare an emergency and to some extent masking the actual circumstances somewhat.
Had this flight departed from an East Coast US airport and continued then we would be correct to point out the dangers and the posibility of all thr engines failing due to say fuel contamination...........however, in this case, the engines put in more hours runing than any engineer would every do on a ground run.
Whay about aircraft in years gone by which shut down engines at cruise to conserve fuel........did the FAA ever have a problem then? - No.
If however the FAA do not follow the standard NTSB investigation scenarios and await findings then perhaps people are justified in saying that this is more political than safety based.
Regards,
DFC