Double Bogie,
As far as I can asertain, they only recovered the aircraft today and the back of a dive support vessel is not the place to start the investigation. Until there is evidence to justify grounding the fleet, EC nor the operators can justify grounding the aircraft.
Similarly I doubt a type can be grounded on the statements of aircrew, pax and observers. The fact there was no mayday or tannoy brief would indicate the crew were too busy flying to know what had caused their predicament.