Nearing the end of a third sightseeing tour on Kaua'i on March 11, a tour helicopter's rotor output shaft and tail rotor blades came loose and fell into the ocean, a preliminary report states.

Pilot Donald Torres tried to execute an autorotation landing, but the aircraft entered into a tight spin and crashed into a YMCA camp, killing one passenger, a National Transportation Safety Board report states.

An initial inspection of the Hughes 500 helicopter, operated by Inter-Island Helicopters Inc., found that the tail rotor gearbox showed breaks typical of overstress fractures, the NTSB report said.

The accident occurred three days after a Heli USA Airways helicopter crashed just miles away, killing four people including the pilot, after reporting hydraulics failures.

In both cases, critical control devices came loose, according to the preliminary NTSB reports.

Shortly before the March 8 crash, pilot Joe Sulak, one of those killed, radioed that he was "having hydraulic problems" and was going to attempt an emergency landing. He later changed his description to a hydraulic "failure."

Moments after that, in his final radio transmission, Sulak said, "OK, we're done."

The helicopter was coming in about 10 feet over the runway when it turned slowly to the left, tipped onto its nose and crashed heavily into the grassy apron, breaking its main rotor blades, crushing the front of the helicopter cabin and causing the AStar's floats to inflate, the NTSB report said.

Separate statements issued by the Federal Aviation Administration and AStar manufacturer Eurocopter said the failure of the control device, known as a "rotor control servo," can result in a pilot's loss of ability to control the AStar helicopter.

Both the FAA and Eurocopter issued statements to flyers about maintenance of the part this week.

FINAL REPORTS

The FAA said its statement was not prompted by the Heli USA crash, and Eurocopter did not identify the crash to which it was responding.

Final reports by the NTSB as to the causes of the two crashes could take a year or more to complete.

Michael Gershon, 60, of Walnut Creek, Calif., died in the March 11 crash. Torres suffered minor injuries, and three other passengers had serious injuries.

Torres told investigators that he "viewed the passengers that got on board, jackets were on, zipped up and secured, life jackets pouches were on and secured, cameras were secured, and they had no hats or bags with them."

The flight had departed Port Allen Airport at 12:10 p.m. on a 55-minute sightseeing tour. The first two flights that day were "waterfall" flights, the NTSB report states.

POST-FLIGHT CHECK

While at a private landing zone during those flights, Torres reported that he shut down the helicopter for about 45 minutes and conducted a post-flight inspection "as we always do."

Among the checks was an examination of the main rotor and tail rotor blades for cracks, the report said. Torres reported that during the earlier flights, the helicopter operated normally and no abnormal vibrations were noted.

About halfway through the third flight, Torres said he was flying over Tunnel Beach and was about 50 yards from the shoreline at 1,000 feet and at 80 knots to 85 knots of airspeed when, within a split second, he heard two loud "bangs" and he "felt it" in his seat and pedals, according to the report.

The pilot reported that he recognized the YMCA campgrounds and decided to execute an autorotation. The helicopter impacted the trees and terrain at the western edge of the campground.

SEARCH FOR PARTS

There were "numerous" witnesses to the crash, according to the report, and one said she heard a loud "pop" and saw two objects falling into the ocean.

Another witness reported that the helicopter "started a slow spiral to the right as it was circling a house" and that the "spiral tightened up and there were two of these tight spirals — the main blades were not turning very rapidly."

The report said divers searched two days for the output shaft and tail rotor blades, both missing from the crash site, but were unable to find the parts and had to suspend their search at Tunnel Beach due to surf conditions.

The Associated Press contributed to this report.