NTSB spokesman Keith Holloway, from Washington, D.C., said that two investigators have been dispatched to Kaua'i. Brian Rayner has been appointed investigator in charge.

Their first task will be to document the scene photographically and to look for failures in the aircraft structure, he said.

Normally, after that process is complete, helicopters involved in crashes are loaded onto a flatbed truck and hauled to a secure area like a hangar at Lihu'e Airport, where NTSB officials join representatives of the aircraft manufacturer and others for a detailed analysis of the wreckage.

In this case, the probe is likely to focus on the A-Star helicopter's hydraulics. Pilot William Joseph Sulak reported by radio before the crash that he was experiencing hydraulic failure on the aircraft while in flight.

Federal Aviation Administration records show that the A-Star helicopter was manufactured in 1979 by Aerospatiale. That company has since been merged into Eurocopter Group.