The National Transportation Safety Board said it had launched an investigation after helicopter, which was carrying five people including a family of four, came down near the USS Arizona Memorial in Pearl Harbour.
Three members of the family were taken to Pali Momi Medical Center in Aiea, Hawaii, a spokesperson for the centre said.Bystanders jumped in to help the passengers. One victim was said to be underwater for about three minutes.
Operations at the visitor centre, including visits to the nearby USS Arizona Memorial, were suspended, the Navy said. The memorial honours the 1,177 sailors and marines killed on the ship in the December 7th, 1941, attack by Japan.
Partial operations at the visitor centre will resume Friday, the National Park Service said. The theatre and boat trips to the Arizona Memorial will be suspended until further notice. The visitor centre grounds, museums, snack shop and bookstore will be open.
Federal Aviation Administration investigators were on their way to the crash site. A National Transportation Safety Board investigator was expected to arrive Friday.
