None of the seven people aboard the Eurocopter AS 350 BA owned by MauiScape Helicopters Inc. was hurt in the incident, which occurred in the same month that two tour helicopters crash-landed on Kaua'i, killing a total of five people.

On March 8, a Heli-USA Eurocopter AS 350 BA experienced a loss of control while landing at Princeville, killing four. On March 11, an Inter-island Helicopters McDonnell Douglas 369FF aircraft crash-landed in Ha'ena after losing its tail rotor. One passenger was killed.

In the Maui incident, the helicopter entered 'Iao Valley near the end of an hourlong sightseeing flight when the pilot noticed a problem with the aircraft's yaw, or side-to-side movement, according to an NTSB preliminary report released this week. The pilot manipulated the tail rotor control pedals to no effect and declared an emergency before landing at the airport's Runway 2, the report said. The helicopter sustained minor damage.

The NTSB said Kahului air-traffic tower personnel told investigators the pilot contacted the tower and reported: "He may have 'lost his tail rotor.' "

A Federal Aviation Administration airworthiness inspector from the Honolulu Flight Standards District Office inspected the helicopter and found that a mounting tang in the tail rotor gearbox pitch-change bellcrank was fractured, the NTSB report said. The gearbox assembly was removed and shipped to the NTSB for further metallurgical examination.

It is expected to take months before the NTSB releases a report on the probable cause of the Maui incident.

NTSB records show there have been four aircraft accidents reported in Hawai'i so far this year, including the three involving tour helicopters last month.