KAUAI, Hawaii -- Investigators Saturday began looking at the wreckage of a Heli USA tour helicopter for clues to why it crashed Thursday, killing four and critically injuring three.

A witness came forward to tell the National Transportation Safety Board that she saw the helicopter plow into the ground nose first.

KITV's Denby Fawcett was in Kauai and reported that an unusually large investigating team, including 16 members from the NTSB, Federal Aviation Administration and the helicopter's manufacturers, searched for clues at the Princeville Airport.

Lead investigator Brian Rayner said the NTSB will look at many factors, including the pilots' report before crashing of hydraulic failure.

"It will be something that will be examined because, again, his comments, and how they were relayed to us through the witnesses, is evidence," Rayner said.

The NTSB said it wants to know when the flotation pontoons deployed, and it will be looking at past crashes of the same type of helicopter. NTSB records showed five A-star crashes nationwide in the last 10 years involving hydraulic failure.

"We cannot confirm that hydraulics was the reason for the crash. It may have been a factor, but I am not in a position to make that statement," said John Power, Vice President of Heli USA.

Heli USA said it paid for family members of the dead and injured passengers and pilot to go to the Princeville Airport.

The company said after the crash that all its A-Stars locally and in Las Vegas were thoroughly inspected.

"And I can confirm our aircaft have been given a full bill of health to operate," Power said.

The wreckage of the A-Star helicopter will be moved Sunday to a hanger ay Lihue Airport for further inspection, officials said.

The NTSB said it expects to have a preliminary report on the cause of the crash in two weeks and a final report in about a year.

The NTSB said part of a larger investigation will be why so many tour helicopters have crashed on Kauai.

There have been five helicopter tour crashes on the Kauai in the last four years.
Related Stories:

• Emergency Crews Face Different Kind Of Recovery
• Victims Identified In Kauai Tour Helicopter Crash