Helicopter spun out before crash that killed coal magnate

Federal officials say the helicopter carrying coal billionaire Chris Cline began spinning before it plunged into the ocean near the Bahamas and killed everyone on board

The National Transportation Safety Board's preliminary report details the July 4 accident and its aftermath but doesn't include a cause. Cline, his daughter Kameron and three of her friends died along with a pilot and copilot in the crash off Cline's private Big Grand Cay island.

The aircraft was leaving the island to take two passengers to Florida for medical treatment, the NTSB said.

A witness saw the helicopter rotate to the left three to four times, followed by a whooshing noises and the sound of an impact, the report said. It was found upside-down in about 16 feet (5 meters) of water with its rotor blades separated. Investigators brought it to a secure site in the United States.

Cline's death led to eulogies from coal industry leaders, government officials and academics, who described him as a visionary and generous philanthropist. He accumulated a $1.8 billion fortune from a career that he began years ago as a coal miner in southern West Virginia. Cline bought Big Grand Cay in 2014.

The full investigation into the crash could take up to two years, a NTSB spokesman said earlier this month.