The pilot of a helicopter that crashed on a sightseeing flight off the Hawaiian island of Kauai last month, killing three passengers, told investigators that the aircraft vibrated and spun before plunging into the water, according to report released Friday.
The National Transportation Safety Board’s preliminary report did not identify a suspected cause of the March 26 accident, but said the pilot said he experienced “a high frequency vibration throughout the helicopter that came in waves and became stronger each time.” The cause won’t be identified until the final report comes out likely sometime next year.





